<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <title>Multiplication Breakdown</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      width: 100%;
      min-height: 100%;
      background: #ffffff;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 12px 8px;
    }

    .equation-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      width: 100%;
      margin-top: 4px;
    }

    .term-box {
      display: flex;
      flex-direction: column;
      align-items: center;
      cursor: pointer;
      user-select: none;
      transition: transform 0.25s ease, opacity 0.25s ease;
    }

    .num-card {
      font-size: 26px;
      font-weight: 800;
      width: 46px;
      height: 46px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 10px;
      border: 2px solid transparent;
      transition: all 0.25s ease;
    }

    .symbol {
      font-size: 22px;
      font-weight: 700;
      color: #64748b;
      display: flex;
      align-items: center;
      justify-content: center;
      width: 24px;
      height: 46px;
    }

    .blue {
      background: #eff6ff;
      border-color: #93c5fd;
      color: #1d4ed8;
    }
    .term-box.active .blue, .term-box:hover .blue {
      background: #2563eb;
      border-color: #1d4ed8;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(37, 99, 235, 0.3);
    }

    .green {
      background: #f0fdf4;
      border-color: #86efac;
      color: #15803d;
    }
    .term-box.active .green, .term-box:hover .green {
      background: #16a34a;
      border-color: #15803d;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(22, 163, 74, 0.3);
    }

    .purple {
      background: #faf5ff;
      border-color: #d8b4fe;
      color: #7e22ce;
      width: 54px;
    }
    .term-box.active .purple, .term-box:hover .purple {
      background: #9333ea;
      border-color: #7e22ce;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(147, 51, 234, 0.3);
    }

    .symbol-btn {
      border-radius: 8px;
      cursor: pointer;
    }
    .symbol-btn.active, .symbol-btn:hover {
      background: #f1f5f9;
      color: #0f172a;
    }

    /* Explanation Area */
    .detail-container {
      width: 100%;
      max-width: 320px;
      min-height: 94px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      text-align: center;
      padding: 8px 12px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      position: relative;
    }

    .detail-badge {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      padding: 3px 8px;
      border-radius: 6px;
      margin-bottom: 4px;
      display: inline-block;
    }

    .badge-blue { background: #dbeafe; color: #1e40af; }
    .badge-gray { background: #e2e8f0; color: #334155; }
    .badge-green { background: #dcfce7; color: #166534; }
    .badge-purple { background: #f3e8ff; color: #6b21a8; }

    .detail-title {
      font-size: 15px;
      font-weight: 700;
      color: #1e2945;
      line-height: 1.2;
    }

    .detail-sub {
      font-size: 13px;
      font-weight: 500;
      color: #64748b;
      margin-top: 2px;
    }

    /* Visual Groups Section */
    .groups-container {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 6px;
      width: 100%;
      max-width: 320px;
      min-height: 72px;
    }

    .group-bag {
      border: 2px dashed #cbd5e1;
      border-radius: 8px;
      padding: 4px 2px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 3px;
      background: #ffffff;
      transition: all 0.25s ease;
    }

    .group-bag.highlight {
      border: 2px solid #2563eb;
      background: #eff6ff;
    }

    .stickers-row {
      display: flex;
      justify-content: center;
      gap: 3px;
    }

    .sticker-dot {
      width: 13px;
      height: 13px;
      border-radius: 50%;
      background: #cbd5e1;
      transition: all 0.25s ease;
    }

    .sticker-dot.active-green {
      background: #16a34a;
      box-shadow: 0 0 4px rgba(22, 163, 74, 0.4);
    }

    .sticker-dot.active-purple {
      background: #9333ea;
      box-shadow: 0 0 4px rgba(147, 51, 234, 0.4);
    }

    .group-tag {
      font-size: 10px;
      font-weight: 700;
      color: #64748b;
    }

    /* Step Navigation Controls */
    .nav-controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      margin-bottom: 2px;
    }

    .step-dot {
      width: 24px;
      height: 24px;
      border-radius: 50%;
      border: 1px solid #cbd5e1;
      background: #f8fafc;
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .step-dot.active {
      background: #1e2945;
      border-color: #1e2945;
      color: #ffffff;
    }

    .nav-btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      font-size: 11px;
      font-weight: 600;
      color: #334155;
      padding: 4px 8px;
      cursor: pointer;
    }
    .nav-btn:hover {
      background: #e2e8f0;
    }
  </style>
</head>
<body>

  
  <div class="equation-row" id="equationRow">
    <div class="term-box active" id="term-0" onclick="setStep(0)">
      <div class="num-card blue">4</div>
    </div>

    <div class="term-box symbol symbol-btn" id="term-1" onclick="setStep(1)">×</div>

    <div class="term-box" id="term-2" onclick="setStep(2)">
      <div class="num-card green">3</div>
    </div>

    <div class="symbol">=</div>

    <div class="term-box" id="term-3" onclick="setStep(3)">
      <div class="num-card purple">12</div>
    </div>
  </div>

  
  <div class="detail-container">
    <span class="detail-badge badge-blue" id="stepBadge">Factor</span>
    <div class="detail-title" id="stepTitle">Number of Groups</div>
    <div class="detail-sub" id="stepSub">4 equal bags</div>
  </div>

  
  <div class="groups-container" id="visualGroups">
    
    <div class="group-bag highlight" id="bag-0">
      <span class="group-tag">Bag 1</span>
      <div class="stickers-row">
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
      </div>
    </div>
    <div class="group-bag highlight" id="bag-1">
      <span class="group-tag">Bag 2</span>
      <div class="stickers-row">
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
      </div>
    </div>
    <div class="group-bag highlight" id="bag-2">
      <span class="group-tag">Bag 3</span>
      <div class="stickers-row">
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
      </div>
    </div>
    <div class="group-bag highlight" id="bag-3">
      <span class="group-tag">Bag 4</span>
      <div class="stickers-row">
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
        <div class="sticker-dot"></div>
      </div>
    </div>
  </div>

  
  <div class="nav-controls">
    <button class="nav-btn" onclick="prevStep()">◀</button>
    <div class="step-dot active" onclick="setStep(0)">1</div>
    <div class="step-dot" onclick="setStep(1)">2</div>
    <div class="step-dot" onclick="setStep(2)">3</div>
    <div class="step-dot" onclick="setStep(3)">4</div>
    <button class="nav-btn" onclick="nextStep()">▶</button>
  </div>

  <script>
    const steps = [
      {
        badge: "Factor",
        badgeClass: "badge-blue",
        title: "Number of Groups",
        sub: "4 equal bags",
        activeTerm: 0,
        highlightBags: [0, 1, 2, 3],
        dotColor: ""
      },
      {
        badge: "Operation",
        badgeClass: "badge-gray",
        title: "means &ldquo;groups of&rdquo;",
        sub: "4 groups of 3",
        activeTerm: 1,
        highlightBags: [0, 1, 2, 3],
        dotColor: ""
      },
      {
        badge: "Factor",
        badgeClass: "badge-green",
        title: "Size of Each Group",
        sub: "3 items in each bag",
        activeTerm: 2,
        highlightBags: [],
        dotColor: "active-green"
      },
      {
        badge: "Product",
        badgeClass: "badge-purple",
        title: "Total Items",
        sub: "12 stickers in all",
        activeTerm: 3,
        highlightBags: [0, 1, 2, 3],
        dotColor: "active-purple"
      }
    ];

    let currentStep = 0;
    let autoTimer = null;

    function renderStep(index) {
      currentStep = index;
      const s = steps[index];

      // Update badge and text
      const badgeEl = document.getElementById("stepBadge");
      badgeEl.className = "detail-badge " + s.badgeClass;
      badgeEl.textContent = s.badge;

      document.getElementById("stepTitle").innerHTML = s.title;
      document.getElementById("stepSub").textContent = s.sub;

      // Update active term in equation
      for (let i = 0; i < 4; i++) {
        const term = document.getElementById("term-" + i);
        if (i === s.activeTerm) {
          term.classList.add("active");
        } else {
          term.classList.remove("active");
        }
      }

      // Update dot buttons
      const dots = document.querySelectorAll(".step-dot");
      dots.forEach((d, i) => {
        d.classList.toggle("active", i === index);
      });

      // Update visual bags
      for (let b = 0; b < 4; b++) {
        const bag = document.getElementById("bag-" + b);
        const shouldHighlight = s.highlightBags.includes(b);
        bag.classList.toggle("highlight", shouldHighlight);

        const stickerDots = bag.querySelectorAll(".sticker-dot");
        stickerDots.forEach(sd => {
          sd.className = "sticker-dot" + (s.dotColor ? " " + s.dotColor : "");
        });
      }
    }

    function setStep(index) {
      clearInterval(autoTimer);
      renderStep(index);
    }

    function nextStep() {
      clearInterval(autoTimer);
      renderStep((currentStep + 1) % steps.length);
    }

    function prevStep() {
      clearInterval(autoTimer);
      renderStep((currentStep - 1 + steps.length) % steps.length);
    }

    // Auto-advance slowly for clear comprehension
    autoTimer = setInterval(() => {
      renderStep((currentStep + 1) % steps.length);
    }, 3800);

    renderStep(0);
  </script>
</body>
</html>

Multiplication as Equal Groups

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    }

    body {
      width: 100%;
      background: #ffffff;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    /* Step Navigation Tabs */
    .tabs {
      display: flex;
      gap: 6px;
      width: 100%;
      max-width: 460px;
      background: #f1f5f9;
      padding: 4px;
      border-radius: 12px;
    }

    .tab-btn {
      flex: 1;
      border: none;
      background: transparent;
      padding: 8px 6px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.25s ease;
      text-align: center;
      user-select: none;
    }

    .tab-btn.active {
      background: #ffffff;
      color: #1e2945;
      box-shadow: 0 2px 6px rgba(30, 41, 69, 0.08);
    }

    /* Stage Area */
    .stage-wrapper {
      position: relative;
      width: 100%;
      max-width: 480px;
      height: 260px;
      margin: 12px 0;
    }

    .step-view {
      position: absolute;
      inset: 0;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s ease, transform 0.3s ease;
      transform: translateY(6px);
    }

    .step-view.active {
      opacity: 1;
      pointer-events: auto;
      transform: translateY(0);
    }

    /* STEP 1: Concrete (Bowls & Cubes) */
    .bowls-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 10px;
      width: 100%;
      padding: 0 8px;
    }

    @media (max-width: 420px) {
      .bowls-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
      }
    }

    .bowl-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
    }

    .bowl {
      width: 100%;
      max-width: 90px;
      aspect-ratio: 1.2;
      background: linear-gradient(180deg, #f8fafc 0%, #e2e8f0 100%);
      border: 2px solid #cbd5e1;
      border-radius: 6px 6px 40px 40px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
      position: relative;
    }

    .cube {
      width: 16px;
      height: 16px;
      border-radius: 3px;
      box-shadow: 1px 2px 0 rgba(0,0,0,0.15);
    }

    .c-orange { background: #ff7849; }
    .c-blue { background: #22b7ff; }
    .c-green { background: #22c55e; }
    .c-purple { background: #a855f7; }

    /* STEP 2: Pictorial (Circles & Bar Model) */
    .pictorial-box {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 20px;
      width: 100%;
    }

    .circle-groups {
      display: flex;
      justify-content: center;
      gap: 12px;
      width: 100%;
    }

    .dot-group {
      width: 58px;
      height: 58px;
      border: 2px dashed #3b82f6;
      border-radius: 50%;
      background: #eff6ff;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
    }

    .math-dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #1e2945;
    }

    /* Bar Model */
    .bar-model-container {
      width: 100%;
      max-width: 320px;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .bar-segments {
      display: flex;
      width: 100%;
      height: 36px;
      border-radius: 6px;
      overflow: hidden;
      border: 2px solid #1e2945;
    }

    .bar-part {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
      background: #dbeafe;
      border-right: 1.5px solid #1e2945;
      font-weight: 700;
      font-size: 15px;
      color: #1e2945;
    }

    .bar-part:last-child {
      border-right: none;
    }

    .bar-bracket {
      width: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
      margin-top: 4px;
    }

    .bracket-line {
      width: 100%;
      height: 6px;
      border-left: 2px solid #1e2945;
      border-right: 2px solid #1e2945;
      border-bottom: 2px solid #1e2945;
      border-radius: 0 0 4px 4px;
    }

    .total-badge {
      margin-top: 4px;
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
    }

    /* STEP 3: Abstract (Equation) */
    .equation-card {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 16px;
    }

    .equation-main {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 38px;
      font-weight: 800;
      color: #1e2945;
    }

    .num-pill {
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .val {
      padding: 4px 14px;
      border-radius: 10px;
      line-height: 1.1;
    }

    .val.v-groups { background: #e0f2fe; color: #0284c7; }
    .val.v-each { background: #fef3c7; color: #d97706; }
    .val.v-total { background: #dcfce7; color: #16a34a; }

    .tag {
      font-size: 11px;
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-top: 6px;
      color: #64748b;
    }

    .op {
      color: #94a3b8;
      font-weight: 600;
      font-size: 28px;
    }

    /* Bottom Status Indicator */
    .indicator-dots {
      display: flex;
      gap: 8px;
      margin-top: 4px;
    }

    .dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: all 0.25s ease;
    }

    .dot.active {
      background: #22b7ff;
      transform: scale(1.25);
    }
  </style>
</head>
<body>

  
  <div class="tabs">
    <button class="tab-btn active" onclick="setStep(0)">1. Concrete</button>
    <button class="tab-btn" onclick="setStep(1)">2. Pictorial</button>
    <button class="tab-btn" onclick="setStep(2)">3. Abstract</button>
  </div>

  
  <div class="stage-wrapper">
    
    <div class="step-view active" id="view-0">
      <div class="bowls-grid">
        <div class="bowl-item">
          <div class="bowl">
            <div class="cube c-orange"></div>
            <div class="cube c-blue"></div>
            <div class="cube c-green"></div>
          </div>
        </div>
        <div class="bowl-item">
          <div class="bowl">
            <div class="cube c-orange"></div>
            <div class="cube c-purple"></div>
            <div class="cube c-green"></div>
          </div>
        </div>
        <div class="bowl-item">
          <div class="bowl">
            <div class="cube c-blue"></div>
            <div class="cube c-purple"></div>
            <div class="cube c-orange"></div>
          </div>
        </div>
        <div class="bowl-item">
          <div class="bowl">
            <div class="cube c-green"></div>
            <div class="cube c-blue"></div>
            <div class="cube c-purple"></div>
          </div>
        </div>
      </div>
    </div>

    
    <div class="step-view" id="view-1">
      <div class="pictorial-box">
        <div class="circle-groups">
          <div class="dot-group">
            <div class="math-dot"></div>
            <div class="math-dot"></div>
            <div class="math-dot"></div>
          </div>
          <div class="dot-group">
            <div class="math-dot"></div>
            <div class="math-dot"></div>
            <div class="math-dot"></div>
          </div>
          <div class="dot-group">
            <div class="math-dot"></div>
            <div class="math-dot"></div>
            <div class="math-dot"></div>
          </div>
          <div class="dot-group">
            <div class="math-dot"></div>
            <div class="math-dot"></div>
            <div class="math-dot"></div>
          </div>
        </div>

        <div class="bar-model-container">
          <div class="bar-segments">
            <div class="bar-part">3</div>
            <div class="bar-part">3</div>
            <div class="bar-part">3</div>
            <div class="bar-part">3</div>
          </div>
          <div class="bar-bracket">
            <div class="bracket-line"></div>
            <span class="total-badge">12</span>
          </div>
        </div>
      </div>
    </div>

    
    <div class="step-view" id="view-2">
      <div class="equation-card">
        <div class="equation-main">
          <div class="num-pill">
            <div class="val v-groups">4</div>
            <span class="tag">groups</span>
          </div>
          <div class="op">×</div>
          <div class="num-pill">
            <div class="val v-each">3</div>
            <span class="tag">in each</span>
          </div>
          <div class="op">=</div>
          <div class="num-pill">
            <div class="val v-total">12</div>
            <span class="tag">total</span>
          </div>
        </div>
      </div>
    </div>
  </div>

  
  <div class="indicator-dots">
    <div class="dot active" onclick="setStep(0)"></div>
    <div class="dot" onclick="setStep(1)"></div>
    <div class="dot" onclick="setStep(2)"></div>
  </div>

  <script>
    let currentStep = 0;
    const tabs = document.querySelectorAll('.tab-btn');
    const views = document.querySelectorAll('.step-view');
    const dots = document.querySelectorAll('.dot');

    function setStep(idx) {
      currentStep = idx;
      tabs.forEach((tab, i) => tab.classList.toggle('active', i === idx));
      views.forEach((view, i) => view.classList.toggle('active', i === idx));
      dots.forEach((dot, i) => dot.classList.toggle('active', i === idx));
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      background: #ffffff;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 16px 12px;
      user-select: none;
    }

    .pots-row {
      display: flex;
      justify-content: center;
      align-items: flex-end;
      gap: 8px;
      width: 100%;
      max-width: 540px;
      margin: 8px 0;
    }

    .pot-card {
      flex: 1;
      min-width: 54px;
      max-width: 96px;
      display: flex;
      flex-direction: column;
      align-items: center;
      opacity: 0.35;
      transition: opacity 0.3s ease, transform 0.3s ease;
      cursor: pointer;
    }

    .pot-card.active {
      opacity: 1;
    }

    .pot-card.current {
      opacity: 1;
      transform: translateY(-4px);
    }

    .flowers {
      font-size: 22px;
      line-height: 1.1;
      letter-spacing: -2px;
      white-space: nowrap;
      filter: drop-shadow(0 2px 3px rgba(0,0,0,0.1));
      margin-bottom: 2px;
      transition: transform 0.3s ease;
    }

    .pot-card.current .flowers {
      transform: scale(1.15);
    }

    .pot-shape {
      width: 100%;
      max-width: 68px;
      height: 42px;
      background: linear-align;
      background: #e07a5f;
      clip-path: polygon(8% 0%, 92% 0%, 80% 100%, 20% 100%);
      border-radius: 2px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

    .pot-rim {
      position: absolute;
      top: 0;
      width: 90%;
      height: 6px;
      background: #c85a3d;
      border-radius: 3px;
    }

    .pot-label {
      color: #ffffff;
      font-size: 11px;
      font-weight: 700;
      margin-top: 4px;
      letter-spacing: 0.5px;
    }

    .count-tag {
      margin-top: 8px;
      background: #f1f5f9;
      color: #64748b;
      font-weight: 800;
      font-size: 15px;
      width: 32px;
      height: 32px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
      box-shadow: 0 0 0 2px transparent;
    }

    .pot-card.active .count-tag {
      background: #fef3c7;
      color: #b45309;
      box-shadow: 0 0 0 2px #f59e0b;
    }

    .pot-card.current .count-tag {
      background: #f59e0b;
      color: #ffffff;
      box-shadow: 0 0 0 3px #d97706;
    }

    .equation-box {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 16px;
      text-align: center;
      width: 100%;
      max-width: 480px;
    }

    .equation-main {
      font-size: 17px;
      font-weight: 800;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px;
    }

    .eq-pill {
      background: #e2e8f0;
      padding: 2px 8px;
      border-radius: 6px;
      transition: all 0.3s ease;
    }

    .eq-pill.active {
      background: #fef3c7;
      color: #b45309;
    }

    .eq-pill.highlight {
      background: #22b7ff;
      color: #ffffff;
    }

    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      margin-top: 4px;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #334155;
      font-size: 13px;
      font-weight: 700;
      padding: 6px 14px;
      border-radius: 8px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s ease;
    }

    .btn:hover {
      background: #e2e8f0;
    }

    .btn-primary {
      background: #22b7ff;
      border-color: #0284c7;
      color: #ffffff;
    }

    .btn-primary:hover {
      background: #0284c7;
    }

    .dots {
      display: flex;
      gap: 6px;
    }

    .dot {
      width: 10px;
      height: 10px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      transition: background 0.2s ease;
    }

    .dot.active {
      background: #22b7ff;
    }
  </style>
</head>
<body>

  <div class="pots-row">
    <div class="pot-card active" id="pot0" onclick="setStep(0)">
      <div class="flowers">🌻🌻</div>
      <div class="pot-shape">
        <div class="pot-rim"></div>
        <span class="pot-label">+2</span>
      </div>
      <div class="count-tag">2</div>
    </div>

    <div class="pot-card active" id="pot1" onclick="setStep(1)">
      <div class="flowers">🌻🌻</div>
      <div class="pot-shape">
        <div class="pot-rim"></div>
        <span class="pot-label">+2</span>
      </div>
      <div class="count-tag">4</div>
    </div>

    <div class="pot-card active" id="pot2" onclick="setStep(2)">
      <div class="flowers">🌻🌻</div>
      <div class="pot-shape">
        <div class="pot-rim"></div>
        <span class="pot-label">+2</span>
      </div>
      <div class="count-tag">6</div>
    </div>

    <div class="pot-card active" id="pot3" onclick="setStep(3)">
      <div class="flowers">🌻🌻</div>
      <div class="pot-shape">
        <div class="pot-rim"></div>
        <span class="pot-label">+2</span>
      </div>
      <div class="count-tag">8</div>
    </div>

    <div class="pot-card active" id="pot4" onclick="setStep(4)">
      <div class="flowers">🌻🌻</div>
      <div class="pot-shape">
        <div class="pot-rim"></div>
        <span class="pot-label">+2</span>
      </div>
      <div class="count-tag">10</div>
    </div>
  </div>

  <div class="equation-box">
    <div class="equation-main">
      <span class="eq-pill" id="eqGroups">5 groups of 2</span>
      <span>=</span>
      <span class="eq-pill" id="eqMult">5 × 2</span>
      <span>=</span>
      <span class="eq-pill highlight" id="eqTotal">10 flowers</span>
    </div>
  </div>

  <div class="controls">
    <button class="btn" id="replayBtn" onclick="restartAnimation()">↻ Replay</button>
    <div class="dots">
      <div class="dot active" onclick="setStep(0)"></div>
      <div class="dot active" onclick="setStep(1)"></div>
      <div class="dot active" onclick="setStep(2)"></div>
      <div class="dot active" onclick="setStep(3)"></div>
      <div class="dot active" onclick="setStep(4)"></div>
    </div>
    <button class="btn btn-primary" id="playBtn" onclick="togglePlay()">⏸</button>
  </div>

  <script>
    let currentStep = 4;
    let isPlaying = false;
    let timer = null;
    const totalSteps = 5;

    function render() {
      for (let i = 0; i < totalSteps; i++) {
        const pot = document.getElementById('pot' + i);
        const dot = document.querySelectorAll('.dot')[i];
        
        if (i <= currentStep) {
          pot.classList.add('active');
          dot.classList.add('active');
        } else {
          pot.classList.remove('active');
          dot.classList.remove('active');
        }

        if (i === currentStep) {
          pot.classList.add('current');
        } else {
          pot.classList.remove('current');
        }
      }

      const count = currentStep + 1;
      const total = count * 2;

      document.getElementById('eqGroups').textContent = `${count} group${count > 1 ? 's' : ''} of 2`;
      document.getElementById('eqMult').textContent = `${count} × 2`;
      document.getElementById('eqTotal').textContent = `${total} flower${total > 1 ? 's' : ''}`;
    }

    function setStep(step) {
      currentStep = step;
      render();
    }

    function nextStep() {
      if (currentStep < totalSteps - 1) {
        currentStep++;
        render();
      } else {
        pause();
      }
    }

    function play() {
      isPlaying = true;
      document.getElementById('playBtn').textContent = '⏸';
      clearInterval(timer);
      timer = setInterval(() => {
        if (currentStep < totalSteps - 1) {
          nextStep();
        } else {
          pause();
        }
      }, 1000);
    }

    function pause() {
      isPlaying = false;
      document.getElementById('playBtn').textContent = '▶';
      clearInterval(timer);
    }

    function togglePlay() {
      if (isPlaying) {
        pause();
      } else {
        if (currentStep >= totalSteps - 1) {
          currentStep = 0;
          render();
        }
        play();
      }
    }

    function restartAnimation() {
      currentStep = 0;
      render();
      play();
    }

    render();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      background: transparent;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      user-select: none;
    }

    .columns {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
    }

    @media (max-width: 440px) {
      .columns {
        grid-template-columns: 1fr;
      }
    }

    .column {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    .header-badge {
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 6px 14px;
      border-radius: 12px;
      width: 100%;
      text-align: center;
    }

    .col-left .header-badge {
      background: #fef3c7;
      border: 1px solid #f59e0b;
    }

    .col-right .header-badge {
      background: #ccfbf1;
      border: 1px solid #0d9488;
    }

    .math-title {
      font-size: 20px;
      font-weight: 800;
      line-height: 1.2;
    }

    .col-left .math-title { color: #92400e; }
    .col-right .math-title { color: #115e59; }

    .math-sub {
      font-size: 13px;
      font-weight: 600;
      opacity: 0.85;
    }

    .trays-container {
      display: flex;
      flex-direction: column;
      gap: 6px;
      width: 100%;
      flex: 1;
      justify-content: center;
    }

    .tray {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      padding: 6px 8px;
      border-radius: 10px;
      cursor: pointer;
      transition: background-color 0.2s ease, box-shadow 0.2s ease;
      min-height: 42px;
    }

    .col-left .tray {
      background: #fffbeb;
      border: 1.5px solid #fde68a;
    }

    .col-left .tray:hover, .col-left .tray.active {
      background: #fef3c7;
      box-shadow: 0 0 0 2px #d97706;
    }

    .col-right .tray {
      background: #f0fdfa;
      border: 1.5px solid #99f6e4;
    }

    .col-right .tray:hover, .col-right .tray.active {
      background: #ccfbf1;
      box-shadow: 0 0 0 2px #0d9488;
    }

    .cookie {
      width: 26px;
      height: 26px;
      flex-shrink: 0;
    }

    .footer-formula {
      font-size: 14px;
      font-weight: 700;
      padding: 4px 10px;
      border-radius: 8px;
      text-align: center;
      width: 100%;
    }

    .col-left .footer-formula {
      background: #fffbeb;
      color: #92400e;
    }

    .col-right .footer-formula {
      background: #f0fdfa;
      color: #115e59;
    }

    .summary-banner {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 8px 12px;
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      text-align: center;
      gap: 2px;
    }

    .summary-title {
      font-size: 14px;
      font-weight: 800;
      color: #0f172a;
    }

    .summary-sub {
      font-size: 12px;
      font-weight: 600;
      color: #64748b;
    }
  </style>
</head>
<body>

  <div class="columns">
    
    <div class="column col-left">
      <div class="header-badge">
        <div class="math-title">3 × 4</div>
        <div class="math-sub">3 groups of 4</div>
      </div>

      <div class="trays-container" id="traysLeft">
        
        <div class="tray" onclick="selectTray(this, 'Group of 4')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
        <div class="tray" onclick="selectTray(this, 'Group of 4')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
        <div class="tray" onclick="selectTray(this, 'Group of 4')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
      </div>

      <div class="footer-formula">4 + 4 + 4 = 12</div>
    </div>

    
    <div class="column col-right">
      <div class="header-badge">
        <div class="math-title">4 × 3</div>
        <div class="math-sub">4 groups of 3</div>
      </div>

      <div class="trays-container" id="traysRight">
        
        <div class="tray" onclick="selectTray(this, 'Group of 3')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
        <div class="tray" onclick="selectTray(this, 'Group of 3')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
        <div class="tray" onclick="selectTray(this, 'Group of 3')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
        <div class="tray" onclick="selectTray(this, 'Group of 3')">
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
          <svg class="cookie" viewBox="0 0 32 32"><circle cx="16" cy="16" r="14" fill="#d97706" stroke="#b45309" stroke-width="1.5"/><circle cx="12" cy="11" r="2" fill="#451a03"/><circle cx="20" cy="12" r="1.8" fill="#451a03"/><circle cx="16" cy="17" r="2.2" fill="#451a03"/><circle cx="11" cy="20" r="1.8" fill="#451a03"/><circle cx="20" cy="21" r="2" fill="#451a03"/></svg>
        </div>
      </div>

      <div class="footer-formula">3 + 3 + 3 + 3 = 12</div>
    </div>
  </div>

  <div class="summary-banner">
    <div class="summary-title" id="summaryTitle">Equal Total: 12 Cookies</div>
    <div class="summary-sub" id="summarySub">3 × 4 = 4 × 3</div>
  </div>

  <script>
    let resetTimer = null;

    function selectTray(el, label) {
      document.querySelectorAll('.tray').forEach(t => t.classList.remove('active'));
      el.classList.add('active');

      const title = document.getElementById('summaryTitle');
      const sub = document.getElementById('summarySub');

      title.textContent = label;
      sub.textContent = 'Tap trays to compare groups';

      clearTimeout(resetTimer);
      resetTimer = setTimeout(() => {
        el.classList.remove('active');
        title.textContent = 'Equal Total: 12 Cookies';
        sub.textContent = '3 × 4 = 4 × 3';
      }, 2000);
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      background-color: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 16px 12px;
      user-select: none;
    }

    .header-text {
      font-size: 15px;
      font-weight: 700;
      color: #64748b;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      margin-bottom: 8px;
    }

    .bags-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 10px;
      width: 100%;
      max-width: 620px;
      margin: auto 0;
    }

    @media (max-width: 460px) {
      .bags-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
      }
    }

    .bag-unit {
      display: flex;
      flex-direction: column;
      align-items: center;
      cursor: pointer;
    }

    .bag-label {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      margin-bottom: 6px;
      transition: color 0.2s ease;
    }

    .bag-card {
      position: relative;
      width: 100%;
      aspect-ratio: 1 / 1.15;
      background: rgba(255, 255, 255, 0.9);
      border: 2px solid #cbd5e1;
      border-radius: 14px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-evenly;
      padding: 10px 6px 6px;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.04);
      transition: border-color 0.25s ease, box-shadow 0.25s ease, background-color 0.25s ease;
    }

    /* Bag top handle visual */
    .bag-card::before {
      content: '';
      position: absolute;
      top: -9px;
      width: 38%;
      height: 12px;
      border: 2px solid #94a3b8;
      border-bottom: none;
      border-radius: 8px 8px 0 0;
      transition: border-color 0.25s ease;
    }

    .bag-unit.active .bag-card {
      border-color: #22b7ff;
      background: #ffffff;
      box-shadow: 0 0 0 3px rgba(34, 183, 255, 0.2), 0 4px 12px rgba(34, 183, 255, 0.15);
    }

    .bag-unit.active .bag-card::before {
      border-color: #22b7ff;
    }

    .bag-unit.active .bag-label {
      color: #0284c7;
    }

    .stars-container {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 4px;
      width: 100%;
    }

    .star-icon {
      width: 24px;
      height: 24px;
      fill: #f59e0b;
      filter: drop-shadow(0 0 3px rgba(245, 158, 11, 0.65));
      transition: transform 0.25s ease, filter 0.25s ease;
    }

    .bag-unit.active .star-icon {
      filter: drop-shadow(0 0 6px rgba(245, 158, 11, 0.95));
      transform: scale(1.08);
    }

    .count-badge {
      font-size: 13px;
      font-weight: 700;
      color: #64748b;
      background: #f1f5f9;
      padding: 2px 8px;
      border-radius: 10px;
    }

    .bag-unit.active .count-badge {
      background: #e0f2fe;
      color: #0369a1;
    }

    .bottom-section {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
      width: 100%;
      margin-top: 10px;
    }

    .primary-phrase {
      font-size: 18px;
      font-weight: 800;
      color: #1e2945;
      text-align: center;
    }

    .math-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 30px;
      padding: 6px 18px;
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
      font-size: 15px;
      font-weight: 700;
    }

    .math-expr {
      color: #475569;
    }

    .math-total {
      color: #0284c7;
      font-weight: 800;
    }
  </style>
</head>
<body>

  <div class="header-text">Tap bags to explore groups</div>

  <div class="bags-grid" id="bagsGrid">
    <div class="bag-unit active" data-index="1">
      <div class="bag-label">Bag 1</div>
      <div class="bag-card">
        <div class="stars-container">
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
        </div>
        <div class="count-badge">3 stars</div>
      </div>
    </div>

    <div class="bag-unit active" data-index="2">
      <div class="bag-label">Bag 2</div>
      <div class="bag-card">
        <div class="stars-container">
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
        </div>
        <div class="count-badge">3 stars</div>
      </div>
    </div>

    <div class="bag-unit active" data-index="3">
      <div class="bag-label">Bag 3</div>
      <div class="bag-card">
        <div class="stars-container">
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
        </div>
        <div class="count-badge">3 stars</div>
      </div>
    </div>

    <div class="bag-unit active" data-index="4">
      <div class="bag-label">Bag 4</div>
      <div class="bag-card">
        <div class="stars-container">
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
          <svg class="star-icon" viewBox="0 0 24 24"><polygon points="12,2 15.09,8.26 22,9.27 17,14.14 18.18,21.02 12,17.77 5.82,21.02 7,14.14 2,9.27 8.91,8.26"/></svg>
        </div>
        <div class="count-badge">3 stars</div>
      </div>
    </div>
  </div>

  <div class="bottom-section">
    <div class="primary-phrase" id="phraseText">4 equal groups of 3</div>
    <div class="math-bar">
      <span class="math-expr" id="addExpr">3 + 3 + 3 + 3</span>
      <span>=</span>
      <span class="math-total" id="multExpr">4 × 3 = 12</span>
    </div>
  </div>

  <script>
    const bags = document.querySelectorAll('.bag-unit');
    const phraseText = document.getElementById('phraseText');
    const addExpr = document.getElementById('addExpr');
    const multExpr = document.getElementById('multExpr');

    function updateDisplay() {
      const activeBags = document.querySelectorAll('.bag-unit.active');
      const count = activeBags.length;

      if (count === 0) {
        phraseText.textContent = '0 groups';
        addExpr.textContent = '0';
        multExpr.textContent = '0 × 3 = 0';
      } else {
        phraseText.textContent = `${count} equal ${count === 1 ? 'group' : 'groups'} of 3`;
        addExpr.textContent = Array(count).fill('3').join(' + ');
        multExpr.textContent = `${count} × 3 = ${count * 3}`;
      }
    }

    bags.forEach(bag => {
      bag.addEventListener('click', () => {
        bag.classList.toggle('active');
        updateDisplay();
      });
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: #ffffff;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 16px;
      user-select: none;
    }
    .diagram-area {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .row-group {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .name-label {
      width: 54px;
      font-size: 16px;
      font-weight: 700;
      color: #1e2945;
      text-align: right;
      flex-shrink: 0;
    }
    .bars-container {
      display: flex;
      align-items: center;
      gap: 6px;
      flex: 1;
    }
    .bar {
      height: 48px;
      background: #22c55e;
      color: #ffffff;
      font-size: 18px;
      font-weight: 700;
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 2px 4px rgba(34, 197, 94, 0.2);
      transition: all 0.3s ease;
    }
    .bar-single {
      width: calc((100% - 12px) / 3);
    }
    .bar-leo {
      flex: 1;
    }
    .bracket-area {
      position: relative;
      margin-left: 66px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
    }
    .bracket-svg {
      width: 100%;
      height: 18px;
      stroke: #64748b;
      stroke-width: 2;
      fill: none;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    .calc-tag {
      font-size: 16px;
      font-weight: 800;
      color: #1e2945;
      background: #f1f5f9;
      padding: 6px 14px;
      border-radius: 20px;
      border: 1px solid #cbd5e1;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .calc-tag span.highlight {
      color: #16a34a;
    }
    .interactive-row {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-top: 4px;
    }
    .step-btn {
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 6px;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .step-btn.active {
      background: #1e2945;
      color: #ffffff;
      border-color: #1e2945;
    }
    .bar-leo.dimmed {
      opacity: 0.2;
      background: #94a3b8;
    }
  </style>
</head>
<body>
  <div class="diagram-area">
    
    <div class="row-group">
      <div class="name-label">Maya</div>
      <div class="bars-container">
        <div class="bar bar-single">6</div>
      </div>
    </div>

    
    <div class="row-group">
      <div class="name-label">Leo</div>
      <div class="bars-container" id="leoBars">
        <div class="bar bar-leo" id="b1">6</div>
        <div class="bar bar-leo" id="b2">6</div>
        <div class="bar bar-leo" id="b3">6</div>
      </div>
    </div>

    
    <div class="bracket-area">
      <svg class="bracket-svg" viewBox="0 0 300 20" preserveAspectRatio="none">
        <path d="M 4 2 Q 4 10 14 10 L 140 10 Q 150 10 150 18 Q 150 10 160 10 L 286 10 Q 296 10 296 2" />
      </svg>
      <div class="calc-tag" id="eqLabel">
        <span class="highlight">?</span> = 3 × 6 = <span class="highlight">18</span>
      </div>
    </div>

    
    <div class="interactive-row">
      <button class="step-btn" id="btn1" onclick="setCount(1)">1 × 6 = 6</button>
      <button class="step-btn" id="btn2" onclick="setCount(2)">2 × 6 = 12</button>
      <button class="step-btn active" id="btn3" onclick="setCount(3)">3 × 6 = 18 (Leo)</button>
    </div>
  </div>

  <script>
    function setCount(n) {
      document.querySelectorAll('.step-btn').forEach((b, i) => {
        b.classList.toggle('active', i + 1 === n);
      });

      const b1 = document.getElementById('b1');
      const b2 = document.getElementById('b2');
      const b3 = document.getElementById('b3');
      const eq = document.getElementById('eqLabel');

      b1.classList.toggle('dimmed', n < 1);
      b2.classList.toggle('dimmed', n < 2);
      b3.classList.toggle('dimmed', n < 3);

      const total = n * 6;
      if (n === 3) {
        eq.innerHTML = '<span class="highlight">?</span> = 3 × 6 = <span class="highlight">18</span>';
      } else {
        eq.innerHTML = `${n} × 6 = <span class="highlight">${total}</span>`;
      }
    }
  </script>
</body>
</html>

Solving Times-as-Many Problems

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: #ffffff;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      padding: 16px;
      user-select: none;
    }
    .diagram-area {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    
    /* Model Rows */
    .model-row {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .row-header {
      display: flex;
      justify-content: space-between;
      align-items: baseline;
      font-size: 15px;
      font-weight: 700;
    }
    .total-badge {
      font-size: 14px;
      font-weight: 700;
      color: #2563eb;
      background: #eff6ff;
      padding: 2px 8px;
      border-radius: 12px;
      border: 1px solid #bfdbfe;
    }
    
    /* Bracket SVG */
    .bracket-container {
      width: 100%;
      height: 14px;
      display: flex;
      align-items: center;
    }
    .bracket-svg {
      width: 100%;
      height: 14px;
    }

    /* Bars */
    .bar-group {
      display: flex;
      gap: 6px;
      width: 100%;
    }
    .bar-box {
      flex: 1;
      height: 48px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 18px;
      font-weight: 800;
      border-radius: 8px;
      transition: all 0.3s ease;
    }
    .pizza-box {
      background: #eff6ff;
      border: 2px solid #3b82f6;
      color: #1d4ed8;
    }
    .lemonade-row .bar-group {
      width: 100%;
      display: flex;
      gap: 6px;
    }
    .lemonade-box {
      flex: 0 0 calc((100% - 18px) / 4);
      width: calc((100% - 18px) / 4);
      max-width: calc((100% - 18px) / 4);
      background: #fefce8;
      border: 2px solid #eab308;
      color: #a16207;
    }

    /* Active Highlight in Solved State */
    .solved .bar-box {
      background: #ecfdf5;
      border-color: #10b981;
      color: #047857;
      box-shadow: 0 2px 6px rgba(16, 185, 129, 0.15);
    }

    /* Calculation Formula Card */
    .calc-card {
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 15px;
      font-weight: 700;
      color: #334155;
      min-height: 46px;
      text-align: center;
      transition: all 0.3s ease;
    }
    .calc-card.active {
      background: #eff6ff;
      border-color: #93c5fd;
      color: #1d4ed8;
    }
    .calc-part {
      transition: color 0.3s ease;
    }
    .calc-result {
      color: #059669;
      font-size: 17px;
      font-weight: 800;
    }

    /* Controls */
    .controls {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-top: 4px;
    }
    .btn-step {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #475569;
      font-size: 13px;
      font-weight: 600;
      padding: 8px 16px;
      border-radius: 20px;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 6px;
      transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
    }
    .btn-step:hover {
      background: #e2e8f0;
    }
    .btn-step.active {
      background: #2563eb;
      border-color: #2563eb;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(37, 99, 235, 0.25);
    }

    @media (max-width: 380px) {
      .row-header {
        font-size: 13px;
      }
      .total-badge {
        font-size: 12px;
        padding: 1px 6px;
      }
      .bar-box {
        height: 42px;
        font-size: 16px;
      }
      .calc-card {
        font-size: 13px;
      }
      .btn-step {
        padding: 6px 12px;
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  <div class="diagram-area" id="diagram">
    
    <div class="model-row">
      <div class="row-header">
        <span>🍕 Pizza ($24)</span>
        <span class="total-badge" id="totalBadge">4 equal parts</span>
      </div>
      
      
      <div class="bracket-container">
        <svg class="bracket-svg" viewBox="0 0 400 14" preserveAspectRatio="none">
          <path d="M 4 12 L 4 4 Q 4 1 10 1 L 194 1 Q 200 1 200 0 Q 200 1 206 1 L 390 1 Q 396 1 396 4 L 396 12" 
                fill="none" stroke="#3b82f6" stroke-width="2" stroke-linecap="round"/>
        </svg>
      </div>

      <div class="bar-group">
        <div class="bar-box pizza-box box-val">?</div>
        <div class="bar-box pizza-box box-val">?</div>
        <div class="bar-box pizza-box box-val">?</div>
        <div class="bar-box pizza-box box-val">?</div>
      </div>
    </div>

    
    <div class="model-row lemonade-row">
      <div class="row-header">
        <span>🍋 Lemonade (1 part)</span>
      </div>
      <div class="bar-group">
        <div class="bar-box lemonade-box box-val">?</div>
      </div>
    </div>

    
    <div class="calc-card" id="calcCard">
      <span class="calc-part" id="calcText">4 equal parts = $24</span>
    </div>

    
    <div class="controls">
      <button class="btn-step active" id="btn0" onclick="setStep(0)">
        <span>1</span> Setup
      </button>
      <button class="btn-step" id="btn1" onclick="setStep(1)">
        <span>2</span> Divide
      </button>
      <button class="btn-step" id="btn2" onclick="setStep(2)">
        <span>3</span> Reveal ($6)
      </button>
    </div>
  </div>

  <script>
    let currentStep = 0;
    const boxes = document.querySelectorAll('.box-val');
    const calcCard = document.getElementById('calcCard');
    const calcText = document.getElementById('calcText');
    const diagram = document.getElementById('diagram');

    function setStep(step) {
      currentStep = step;
      
      // Update buttons
      document.getElementById('btn0').classList.toggle('active', step === 0);
      document.getElementById('btn1').classList.toggle('active', step === 1);
      document.getElementById('btn2').classList.toggle('active', step === 2);

      if (step === 0) {
        diagram.classList.remove('solved');
        calcCard.classList.remove('active');
        boxes.forEach(b => b.textContent = '?');
        calcText.innerHTML = '4 equal parts = $24';
      } else if (step === 1) {
        diagram.classList.remove('solved');
        calcCard.classList.add('active');
        boxes.forEach(b => b.textContent = '?');
        calcText.innerHTML = '$24 ÷ 4 parts = <span class="calc-result">$6</span> per box';
      } else if (step === 2) {
        diagram.classList.add('solved');
        calcCard.classList.add('active');
        boxes.forEach(b => b.textContent = '$6');
        calcText.innerHTML = 'Each part = <span class="calc-result">$6</span> (Lemonade is $6)';
      }
    }
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 16px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      user-select: none;
    }

    .diagram-wrap {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }

    /* Mode Selector Buttons */
    .view-toggles {
      display: flex;
      gap: 8px;
      background: #f1f5f9;
      padding: 4px;
      border-radius: 10px;
    }
    .toggle-btn {
      flex: 1;
      padding: 8px 12px;
      font-size: 14px;
      font-weight: 600;
      border: none;
      background: transparent;
      color: #64748b;
      border-radius: 7px;
      cursor: pointer;
      transition: all 0.25s ease;
      text-align: center;
    }
    .toggle-btn.active {
      background: #ffffff;
      color: #6d28d9;
      box-shadow: 0 2px 6px rgba(109, 40, 217, 0.12);
    }

    /* Tape Diagram Area */
    .tape-container {
      position: relative;
      display: flex;
      flex-direction: column;
      gap: 14px;
      padding: 12px 14px 12px 14px;
      background: #faf5ff;
      border-radius: 16px;
      border: 2px dashed #ddd6fe;
    }

    .row {
      display: flex;
      align-items: center;
      gap: 12px;
    }

    .row-label {
      width: 70px;
      font-size: 14px;
      font-weight: 700;
      color: #4c1d95;
      text-align: right;
      flex-shrink: 0;
    }

    .bars-group {
      display: flex;
      gap: 6px;
      flex: 1;
    }

    .bar {
      flex: 1;
      height: 48px;
      background: #8b5cf6;
      color: #ffffff;
      font-size: 18px;
      font-weight: 800;
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
      box-shadow: 0 3px 0 #6d28d9;
      transition: all 0.3s ease;
      cursor: pointer;
    }

    .bar .unit-tag {
      position: absolute;
      top: -9px;
      font-size: 10px;
      font-weight: 700;
      background: #ede9fe;
      color: #6d28d9;
      padding: 1px 6px;
      border-radius: 10px;
      border: 1px solid #c4b5fd;
      opacity: 0;
      transform: translateY(3px);
      transition: all 0.3s ease;
    }

    .bar.unit-mode .unit-tag {
      opacity: 1;
      transform: translateY(0);
    }

    .row-total {
      font-size: 15px;
      font-weight: 700;
      color: #5b21b6;
      width: 44px;
      text-align: left;
      flex-shrink: 0;
      transition: opacity 0.3s ease;
    }

    /* Summary Card / Big Bracket Area */
    .summary-card {
      background: #f8fafc;
      border-radius: 12px;
      border: 1px solid #e2e8f0;
      padding: 12px 16px;
      display: flex;
      flex-direction: column;
      gap: 6px;
      text-align: center;
      transition: background 0.3s ease;
    }

    .total-title {
      font-size: 12px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      color: #64748b;
    }

    .equation-display {
      font-size: 20px;
      font-weight: 800;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
    }

    .eq-accent {
      color: #7c3aed;
    }
    .eq-pill {
      background: #ede9fe;
      color: #6d28d9;
      padding: 2px 8px;
      border-radius: 6px;
    }

    .shortcut-hint {
      font-size: 13px;
      font-weight: 600;
      color: #6b7280;
    }

    /* Multiplier indicator */
    .times-marker {
      display: flex;
      align-items: center;
      justify-content: flex-end;
      gap: 4px;
      font-size: 12px;
      font-weight: 700;
      color: #7c3aed;
      padding-right: 56px;
      margin-top: -6px;
    }
  </style>
</head>
<body>

<div class="diagram-wrap">
  
  <div class="view-toggles">
    <button class="toggle-btn active" id="btnByDays" onclick="setMode('parts')">Day by Day</button>
    <button class="toggle-btn" id="btnByUnits" onclick="setMode('units')">Unit Shortcut</button>
  </div>

  
  <div class="tape-container">
    
    <div class="row">
      <div class="row-label">Monday</div>
      <div class="bars-group" style="flex: 0 0 25%;">
        <div class="bar" id="bar1">
          <span class="unit-tag">Unit 1</span>
          8
        </div>
      </div>
      <div class="row-total" id="mTotal">= 8</div>
    </div>

    
    <div class="row">
      <div class="row-label">Tuesday</div>
      <div class="bars-group" style="flex: 0 0 75%;">
        <div class="bar" id="bar2">
          <span class="unit-tag">Unit 2</span>
          8
        </div>
        <div class="bar" id="bar3">
          <span class="unit-tag">Unit 3</span>
          8
        </div>
        <div class="bar" id="bar4">
          <span class="unit-tag">Unit 4</span>
          8
        </div>
      </div>
      <div class="row-total" id="tTotal">= 24</div>
    </div>

    <div class="times-marker">
      <span>3 × as many as Monday (3 × 8 = 24)</span>
    </div>
  </div>

  
  <div class="summary-card" id="summaryCard">
    <div class="total-title">Total Pages Read</div>
    <div class="equation-display" id="equation">
      <span>8</span> + <span>24</span> = <span class="eq-accent">32</span>
    </div>
    <div class="shortcut-hint" id="hint">
      Monday (8) + Tuesday (24)
    </div>
  </div>
</div>

<script>
  let currentMode = 'parts';

  function setMode(mode) {
    currentMode = mode;
    const btnDays = document.getElementById('btnByDays');
    const btnUnits = document.getElementById('btnByUnits');
    const bars = document.querySelectorAll('.bar');
    const eq = document.getElementById('equation');
    const hint = document.getElementById('hint');
    const mTotal = document.getElementById('mTotal');
    const tTotal = document.getElementById('tTotal');

    if (mode === 'units') {
      btnUnits.classList.add('active');
      btnDays.classList.remove('active');
      bars.forEach(b => b.classList.add('unit-mode'));
      mTotal.style.opacity = '0.3';
      tTotal.style.opacity = '0.3';
      eq.innerHTML = '<span class="eq-pill">4 units</span> × <span>8</span> = <span class="eq-accent">32</span>';
      hint.textContent = 'Shortcut: 1 unit + 3 units = 4 units of 8';
    } else {
      btnDays.classList.add('active');
      btnUnits.classList.remove('active');
      bars.forEach(b => b.classList.remove('unit-mode'));
      mTotal.style.opacity = '1';
      tTotal.style.opacity = '1';
      eq.innerHTML = '<span>8</span> + <span>24</span> = <span class="eq-accent">32</span>';
      hint.textContent = 'Monday (8) + Tuesday (24)';
    }
  }

  // Allow clicking bars to toggle view
  document.querySelectorAll('.bar').forEach(bar => {
    bar.addEventListener('click', () => {
      setMode(currentMode === 'parts' ? 'units' : 'parts');
    });
  });
</script>

</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-tap-highlight-color: transparent;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 12px;
      width: 100%;
      max-width: 600px;
    }

    @media (max-width: 440px) {
      .grid {
        grid-template-columns: 1fr;
        gap: 10px;
      }
    }

    .panel {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 14px 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      box-shadow: 0 1px 3px rgba(0,0,0,0.04);
      cursor: pointer;
      user-select: none;
      transition: border-color 0.2s ease, box-shadow 0.2s ease;
    }

    .panel:hover {
      border-color: #cbd5e1;
      box-shadow: 0 3px 8px rgba(0,0,0,0.06);
    }

    .panel.active {
      border-color: #3b82f6;
      box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
    }

    .title {
      font-size: 15px;
      font-weight: 700;
      color: #0f172a;
      text-align: center;
      margin-bottom: 12px;
      letter-spacing: -0.2px;
    }

    .visual-stage {
      width: 100%;
      height: 140px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 6px;
    }

    /* Left Side: 1 bar of 5 + 4 single units */
    .more-row {
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .bar-5 {
      display: grid;
      grid-template-columns: repeat(5, 1fr);
      width: 110px;
      height: 26px;
      background: #3b82f6;
      border-radius: 6px;
      border: 2px solid #2563eb;
      overflow: hidden;
      position: relative;
    }

    .bar-5 .segment {
      border-right: 1px solid rgba(255, 255, 255, 0.4);
      height: 100%;
    }

    .bar-5 .segment:last-child {
      border-right: none;
    }

    .bar-label {
      position: absolute;
      inset: 0;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #ffffff;
      font-weight: 800;
      font-size: 13px;
      pointer-events: none;
      text-shadow: 0 1px 2px rgba(0,0,0,0.2);
    }

    .unit-group {
      display: flex;
      gap: 3px;
    }

    .unit-1 {
      width: 18px;
      height: 26px;
      background: #f97316;
      border: 2px solid #ea580c;
      border-radius: 5px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #ffffff;
      font-size: 11px;
      font-weight: 800;
      transition: transform 0.2s ease;
    }

    .plus-symbol {
      font-size: 16px;
      font-weight: 800;
      color: #ea580c;
      margin: 0 1px;
    }

    /* Right Side: 4 bars of 5 */
    .times-list {
      display: flex;
      flex-direction: column;
      gap: 5px;
      width: 100%;
      align-items: center;
    }

    .times-item {
      display: flex;
      align-items: center;
      gap: 6px;
      transition: transform 0.2s ease;
    }

    .times-count {
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      width: 14px;
      text-align: right;
    }

    /* Equation Badges */
    .equation {
      margin-top: 12px;
      font-size: 16px;
      font-weight: 800;
      padding: 6px 14px;
      border-radius: 8px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    .equation-add {
      background: #fff7ed;
      color: #ea580c;
      border: 1px solid #fed7aa;
    }

    .equation-mult {
      background: #eff6ff;
      color: #2563eb;
      border: 1px solid #bfdbfe;
    }

    .hl-blue {
      color: #2563eb;
    }

    .hl-orange {
      color: #ea580c;
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="panel active" id="panelAdd" onclick="selectPanel('add')">
      <div class="title">4 More Than 5</div>
      
      <div class="visual-stage">
        <div class="more-row">
          <div class="bar-5">
            <div class="segment"></div>
            <div class="segment"></div>
            <div class="segment"></div>
            <div class="segment"></div>
            <div class="segment"></div>
            <span class="bar-label">5</span>
          </div>

          <span class="plus-symbol">+</span>

          <div class="unit-group">
            <div class="unit-1">1</div>
            <div class="unit-1">1</div>
            <div class="unit-1">1</div>
            <div class="unit-1">1</div>
          </div>
        </div>
      </div>

      <div class="equation equation-add">
        <span class="hl-blue">5</span> + <span class="hl-orange">4</span> = 9
      </div>
    </div>

    
    <div class="panel" id="panelMult" onclick="selectPanel('mult')">
      <div class="title">4 Times As Many</div>
      
      <div class="visual-stage">
        <div class="times-list">
          <div class="times-item">
            <span class="times-count">1</span>
            <div class="bar-5">
              <div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div>
              <span class="bar-label">5</span>
            </div>
          </div>
          <div class="times-item">
            <span class="times-count">2</span>
            <div class="bar-5">
              <div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div>
              <span class="bar-label">5</span>
            </div>
          </div>
          <div class="times-item">
            <span class="times-count">3</span>
            <div class="bar-5">
              <div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div>
              <span class="bar-label">5</span>
            </div>
          </div>
          <div class="times-item">
            <span class="times-count">4</span>
            <div class="bar-5">
              <div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div><div class="segment"></div>
              <span class="bar-label">5</span>
            </div>
          </div>
        </div>
      </div>

      <div class="equation equation-mult">
        4 × <span class="hl-blue">5</span> = 20
      </div>
    </div>
  </div>

  <script>
    function selectPanel(type) {
      document.getElementById('panelAdd').classList.toggle('active', type === 'add');
      document.getElementById('panelMult').classList.toggle('active', type === 'mult');
    }
  </script>
</body>
</html>

OGM.4.OA.1

Aligned learning resources

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