<!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 {
      background: #f8fafc;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
    }

    .main-grid {
      width: 100%;
      max-width: 640px;
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .nav-tabs {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-bottom: 2px;
    }

    .tab-btn {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      padding: 6px 14px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
      color: #64748b;
      cursor: pointer;
      box-shadow: 0 1px 2px rgba(0,0,0,0.04);
      transition: all 0.2s ease;
    }

    .tab-btn.active {
      background: #2563eb;
      color: #ffffff;
      border-color: #2563eb;
      box-shadow: 0 2px 6px rgba(37,99,235,0.25);
    }

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

    @media (max-width: 480px) {
      .cards-container {
        grid-template-columns: 1fr;
      }
    }

    .example-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 14px;
      padding: 12px 14px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      box-shadow: 0 2px 6px rgba(0,0,0,0.03);
      position: relative;
      transition: opacity 0.25s ease, transform 0.25s ease;
    }

    .card-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      border-bottom: 1px solid #f1f5f9;
      padding-bottom: 8px;
    }

    .place-badge {
      font-size: 12px;
      font-weight: 700;
      color: #1e2945;
      display: flex;
      align-items: center;
      gap: 5px;
    }

    .tag {
      font-size: 10px;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      padding: 2px 6px;
      border-radius: 4px;
      font-weight: 700;
    }

    .tag-blue {
      background: #eff6ff;
      color: #2563eb;
    }

    /* Number Display Area */
    .num-display {
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 26px;
      font-weight: 700;
      letter-spacing: 2px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 4px 6px;
      position: relative;
      user-select: none;
    }

    .digit-box {
      display: inline-flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      min-width: 22px;
    }

    /* Visual indicators */
    .target-digit {
      color: #2563eb;
      position: relative;
    }

    .target-digit::after {
      content: '';
      position: absolute;
      bottom: -3px;
      left: 2px;
      right: 2px;
      height: 3px;
      background: #2563eb;
      border-radius: 2px;
    }

    .decider-orange {
      color: #d97706;
      background: #fef3c7;
      border: 2px solid #d97706;
      border-radius: 50%;
      width: 28px;
      height: 28px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 1px;
    }

    .decider-purple {
      color: #7c3aed;
      background: #f3e8ff;
      border: 2px solid #7c3aed;
      border-radius: 50%;
      width: 28px;
      height: 28px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 1px;
    }

    .cut-line {
      width: 2px;
      height: 24px;
      background: #cbd5e1;
      border-left: 2px dashed #94a3b8;
      margin: 0 3px;
    }

    .drop-digits {
      color: #94a3b8;
      text-decoration: line-through;
      opacity: 0.65;
    }

    /* Labels below digits */
    .labels-row {
      display: flex;
      justify-content: space-between;
      font-size: 11px;
      font-weight: 600;
      padding: 0 4px;
    }

    .lbl-target {
      color: #2563eb;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .lbl-decider-orange {
      color: #d97706;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .lbl-decider-purple {
      color: #7c3aed;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    /* Rule & Outcome Step Box */
    .step-box {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 8px;
      padding: 8px 10px;
      display: flex;
      flex-direction: column;
      gap: 6px;
      font-size: 12px;
    }

    .rule-line {
      display: flex;
      align-items: center;
      gap: 6px;
      font-weight: 600;
    }

    .badge-check {
      display: inline-flex;
      align-items: center;
      padding: 2px 7px;
      border-radius: 12px;
      font-size: 11px;
      font-weight: 700;
    }

    .badge-orange {
      background: #fffbeb;
      color: #b45309;
      border: 1px solid #fde68a;
    }

    .badge-purple {
      background: #faf5ff;
      color: #6b21a8;
      border: 1px solid #e9d5ff;
    }

    .result-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      background: #f1f5f9;
      border-radius: 6px;
      padding: 6px 10px;
      margin-top: 2px;
    }

    .result-label {
      font-size: 11px;
      font-weight: 700;
      color: #64748b;
      text-transform: uppercase;
    }

    .result-val {
      font-size: 16px;
      font-weight: 800;
      color: #0f172a;
      letter-spacing: 0.5px;
    }

    .result-val span {
      color: #2563eb;
    }

    /* Filter Views */
    .view-card1 #card2 {
      display: none;
    }
    .view-card1 #card1 {
      grid-column: 1 / -1;
    }

    .view-card2 #card1 {
      display: none;
    }
    .view-card2 #card2 {
      grid-column: 1 / -1;
    }
  </style>
</head>
<body>

  <div class="main-grid" id="mainContainer">
    
    <div class="nav-tabs">
      <button class="tab-btn active" id="tabBoth" onclick="setView('both')">Compare Both</button>
      <button class="tab-btn" id="tabTenths" onclick="setView('tenths')">1 d.p. (Tenths)</button>
      <button class="tab-btn" id="tabHund" onclick="setView('hundredths')">2 d.p. (Hundredths)</button>
    </div>

    
    <div class="cards-container" id="cardsGrid">
      
      
      <div class="example-card" id="card1">
        <div class="card-header">
          <div class="place-badge">
            <span>1 Decimal Place</span>
          </div>
          <span class="tag tag-blue">Tenths</span>
        </div>

        
        <div class="num-display">
          <span>14.</span>
          <div class="digit-box">
            <span class="target-digit">7</span>
          </div>
          <div class="cut-line"></div>
          <div class="decider-orange">3</div>
          <span class="drop-digits">82</span>
        </div>

        <div class="labels-row">
          <span class="lbl-target">▲ Target (7)</span>
          <span class="lbl-decider-orange">● Decider (3)</span>
        </div>

        
        <div class="step-box">
          <div class="rule-line">
            <span class="badge-check badge-orange">3 &lt; 5</span>
            <span>Keep target digit (7)</span>
          </div>
          <div class="result-row">
            <span class="result-label">Rounded Result</span>
            <span class="result-val">14.<span>7</span></span>
          </div>
        </div>
      </div>

      
      <div class="example-card" id="card2">
        <div class="card-header">
          <div class="place-badge">
            <span>2 Decimal Places</span>
          </div>
          <span class="tag tag-blue">Hundredths</span>
        </div>

        
        <div class="num-display">
          <span>14.7</span>
          <div class="digit-box">
            <span class="target-digit">3</span>
          </div>
          <div class="cut-line"></div>
          <div class="decider-purple">8</div>
          <span class="drop-digits">2</span>
        </div>

        <div class="labels-row">
          <span class="lbl-target">▲ Target (3)</span>
          <span class="lbl-decider-purple">● Decider (8)</span>
        </div>

        
        <div class="step-box">
          <div class="rule-line">
            <span class="badge-check badge-purple">8 ≥ 5</span>
            <span>Round target up (3 → 4)</span>
          </div>
          <div class="result-row">
            <span class="result-label">Rounded Result</span>
            <span class="result-val">14.7<span>4</span></span>
          </div>
        </div>
      </div>

    </div>
  </div>

  <script>
    function setView(view) {
      const grid = document.getElementById('cardsGrid');
      const bBoth = document.getElementById('tabBoth');
      const bTenths = document.getElementById('tabTenths');
      const bHund = document.getElementById('tabHund');

      [bBoth, bTenths, bHund].forEach(b => b.classList.remove('active'));
      grid.classList.remove('view-card1', 'view-card2');

      if (view === 'tenths') {
        grid.classList.add('view-card1');
        bTenths.classList.add('active');
      } else if (view === 'hundredths') {
        grid.classList.add('view-card2');
        bHund.classList.add('active');
      } else {
        bBoth.classList.add('active');
      }
    }
  </script>
</body>
</html>

Rounding Numbers to Specified Decimal Places

<!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">
  <title>Rounding Cascade Diagram</title>
  <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;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 10px;
      user-select: none;
    }

    /* Controls Bar */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      width: 100%;
      max-width: 480px;
      margin-bottom: 6px;
    }
    .btn-step {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      color: #475569;
      font-size: 13px;
      font-weight: 600;
      padding: 6px 10px;
      border-radius: 8px;
      cursor: pointer;
      transition: all 0.2s ease;
      flex: 1;
      text-align: center;
    }
    .btn-step.active {
      background: #2563eb;
      color: #ffffff;
      border-color: #2563eb;
      box-shadow: 0 2px 6px rgba(37,99,235,0.25);
    }
    .btn-play {
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      font-size: 14px;
      padding: 6px 12px;
      border-radius: 8px;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* Main Stage */
    .stage {
      position: relative;
      width: 100%;
      max-width: 480px;
      height: 285px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
    }

    /* Digit Strip */
    .digit-row {
      display: flex;
      align-items: flex-end;
      justify-content: center;
      gap: 5px;
      position: relative;
      margin-top: 25px;
      margin-bottom: 20px;
    }

    .digit-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
    }

    .place-tag {
      font-size: 10.5px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 4px;
      color: #94a3b8;
      transition: color 0.3s ease;
      white-space: nowrap;
    }

    .digit-box {
      width: 44px;
      height: 52px;
      background: #f8fafc;
      border: 2px solid #e2e8f0;
      border-radius: 10px;
      font-size: 26px;
      font-weight: 700;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
      position: relative;
    }

    .dot-box {
      width: 16px;
      font-size: 30px;
      font-weight: 800;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      padding-bottom: 6px;
    }

    /* Carry Tag */
    .carry-bubble {
      position: absolute;
      top: -26px;
      font-size: 13px;
      font-weight: 800;
      background: #ef4444;
      color: white;
      padding: 2px 7px;
      border-radius: 12px;
      opacity: 0;
      transform: translateY(6px);
      transition: all 0.3s ease;
      box-shadow: 0 2px 6px rgba(239, 68, 68, 0.3);
    }
    .carry-bubble.visible {
      opacity: 1;
      transform: translateY(0);
    }

    /* Carry Arrow SVG */
    .carry-svg {
      position: absolute;
      top: -28px;
      left: 102px;
      width: 75px;
      height: 32px;
      pointer-events: none;
      opacity: 0;
      transition: opacity 0.3s ease;
    }
    .carry-svg.visible {
      opacity: 1;
    }

    /* Drop / Cutoff Overlay */
    .cutoff-line {
      position: absolute;
      right: 98px;
      top: 15px;
      bottom: -5px;
      width: 2px;
      border-left: 2px dashed #cbd5e1;
      opacity: 0;
      transition: opacity 0.3s ease;
    }
    .cutoff-line.visible {
      opacity: 1;
    }

    /* Explanatory Banner */
    .action-badge {
      font-size: 14px;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 20px;
      background: #f1f5f9;
      color: #334155;
      margin-top: 4px;
      min-height: 32px;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      transition: all 0.3s ease;
    }

    /* Final Card */
    .result-box {
      margin-top: 10px;
      padding: 10px 18px;
      background: #f0fdf4;
      border: 2px solid #22c55e;
      border-radius: 12px;
      display: flex;
      align-items: center;
      gap: 14px;
      opacity: 0;
      transform: scale(0.95);
      transition: all 0.3s ease;
      box-shadow: 0 4px 12px rgba(34, 197, 94, 0.15);
    }
    .result-box.visible {
      opacity: 1;
      transform: scale(1);
    }
    .result-num {
      font-size: 30px;
      font-weight: 800;
      color: #15803d;
      letter-spacing: 1px;
    }
    .result-note {
      font-size: 12px;
      font-weight: 600;
      color: #166534;
      line-height: 1.3;
      border-left: 2px solid #86efac;
      padding-left: 10px;
    }

    /* Step Specific Highlights */
    .target-highlight {
      border-color: #2563eb !important;
      background: #eff6ff !important;
      color: #1d4ed8 !important;
      box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
    }
    .decider-highlight {
      border-color: #d97706 !important;
      background: #fffbeb !important;
      color: #b45309 !important;
      box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.2);
    }
    .changed-highlight {
      border-color: #16a34a !important;
      background: #f0fdf4 !important;
      color: #15803d !important;
      box-shadow: 0 0 0 3px rgba(22, 163, 74, 0.2);
    }
    .dropped {
      opacity: 0.25;
      text-decoration: line-through;
      border-style: dashed !important;
    }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="btn-step active" id="btn0" onclick="setStep(0)">1. Identify</button>
    <button class="btn-step" id="btn1" onclick="setStep(1)">2. Round Up</button>
    <button class="btn-step" id="btn2" onclick="setStep(2)">3. Cascade</button>
    <button class="btn-step" id="btn3" onclick="setStep(3)">4. Result</button>
    <button class="btn-play" id="playBtn" onclick="togglePlay()" title="Auto Play">⏸</button>
  </div>

  
  <div class="stage">

    <div class="cutoff-line" id="cutoffLine"></div>

    
    <svg class="carry-svg" id="carrySvg" viewBox="0 0 75 32">
      <defs>
        <marker id="arrow" viewBox="0 0 6 6" refX="5" refY="3" markerWidth="4" markerHeight="4" orient="auto-start-reverse">
          <path d="M 0 0 L 6 3 L 0 6 z" fill="#ef4444" />
        </marker>
      </defs>
      <path d="M 68 25 Q 38 2 8 25" fill="none" stroke="#ef4444" stroke-width="2.5" stroke-dasharray="3,3" marker-end="url(#arrow)" />
    </svg>

    
    <div class="digit-row">
      
      <div class="digit-col">
        <span class="place-tag">Ones</span>
        <div class="digit-box" id="box-ones">8</div>
      </div>

      <div class="dot-box">.</div>

      
      <div class="digit-col">
        <div class="carry-bubble" id="carryTenths">+1</div>
        <span class="place-tag" id="tag-tenths">Tenths</span>
        <div class="digit-box" id="box-tenths">2</div>
      </div>

      
      <div class="digit-col">
        <div class="carry-bubble" id="carryHundredths">+1</div>
        <span class="place-tag" id="tag-hundredths">Hundredths</span>
        <div class="digit-box" id="box-hundredths">9</div>
      </div>

      
      <div class="digit-col">
        <span class="place-tag" id="tag-decider">Decider</span>
        <div class="digit-box" id="box-decider">7</div>
      </div>

      
      <div class="digit-col">
        <span class="place-tag">Drop</span>
        <div class="digit-box" id="box-last">1</div>
      </div>
    </div>

    
    <div class="action-badge" id="actionBadge">
      Target: <b>9</b> &nbsp;|&nbsp; Decider: <b>7</b>
    </div>

    
    <div class="result-box" id="resultBox">
      <div class="result-num">8.30</div>
      <div class="result-note">Keep trailing <b>0</b> for<br>2 decimal places!</div>
    </div>

  </div>

  <script>
    let currentStep = 0;
    let isPlaying = true;
    let timer = null;

    const bOnes = document.getElementById('box-ones');
    const bTenths = document.getElementById('box-tenths');
    const bHundredths = document.getElementById('box-hundredths');
    const bDecider = document.getElementById('box-decider');
    const bLast = document.getElementById('box-last');

    const tagTenths = document.getElementById('tag-tenths');
    const tagHundredths = document.getElementById('tag-hundredths');
    const tagDecider = document.getElementById('tag-decider');

    const carryTenths = document.getElementById('carryTenths');
    const carryHundredths = document.getElementById('carryHundredths');
    const carrySvg = document.getElementById('carrySvg');
    const cutoffLine = document.getElementById('cutoffLine');

    const actionBadge = document.getElementById('actionBadge');
    const resultBox = document.getElementById('resultBox');

    function resetVisuals() {
      // Clear classes
      [bOnes, bTenths, bHundredths, bDecider, bLast].forEach(el => {
        el.className = 'digit-box';
      });
      [tagTenths, tagHundredths, tagDecider].forEach(el => el.style.color = '#94a3b8');

      carryTenths.classList.remove('visible');
      carryHundredths.classList.remove('visible');
      carrySvg.classList.remove('visible');
      cutoffLine.classList.remove('visible');
      resultBox.classList.remove('visible');

      bTenths.textContent = '2';
      bHundredths.textContent = '9';
      bDecider.textContent = '7';
      bLast.textContent = '1';

      for (let i = 0; i < 4; i++) {
        document.getElementById('btn' + i).classList.remove('active');
      }
      document.getElementById('btn' + currentStep).classList.add('active');
    }

    function renderStep(step) {
      resetVisuals();
      currentStep = step;

      if (step === 0) {
        // Step 1: Identify
        bHundredths.classList.add('target-highlight');
        tagHundredths.style.color = '#2563eb';
        bDecider.classList.add('decider-highlight');
        tagDecider.style.color = '#d97706';

        actionBadge.innerHTML = 'Target: <b>[9]</b> &nbsp;← Decider: <b>(7)</b>';
        actionBadge.style.color = '#1e2945';
        actionBadge.style.background = '#f1f5f9';
      } 
      else if (step === 1) {
        // Step 2: Decider >= 5
        bHundredths.classList.add('target-highlight');
        bDecider.classList.add('decider-highlight');
        carryHundredths.classList.add('visible');

        actionBadge.innerHTML = '<b>7 ≥ 5</b> &nbsp;→&nbsp; Add <b>+1</b> to hundredths';
        actionBadge.style.color = '#9a3412';
        actionBadge.style.background = '#ffedd5';
      } 
      else if (step === 2) {
        // Step 3: Cascade Carry
        bHundredths.textContent = '0';
        bHundredths.classList.add('changed-highlight');
        bTenths.classList.add('target-highlight');
        tagTenths.style.color = '#2563eb';

        carryTenths.classList.add('visible');
        carrySvg.classList.add('visible');

        bDecider.classList.add('dropped');
        bLast.classList.add('dropped');
        cutoffLine.classList.add('visible');

        actionBadge.innerHTML = '<b>9 + 1 = 10</b> &nbsp;→&nbsp; write <b>0</b>, carry <b>+1</b>';
        actionBadge.style.color = '#1e40af';
        actionBadge.style.background = '#dbeafe';
      } 
      else if (step === 3) {
        // Step 4: Final Resolved
        bTenths.textContent = '3';
        bTenths.classList.add('changed-highlight');
        bHundredths.textContent = '0';
        bHundredths.classList.add('changed-highlight');

        bDecider.classList.add('dropped');
        bLast.classList.add('dropped');
        cutoffLine.classList.add('visible');

        actionBadge.innerHTML = '<b>2 + 1 = 3</b> in tenths place';
        actionBadge.style.color = '#166534';
        actionBadge.style.background = '#dcfce7';

        resultBox.classList.add('visible');
      }
    }

    function setStep(idx) {
      currentStep = idx;
      renderStep(currentStep);
    }

    function nextStep() {
      currentStep = (currentStep + 1) % 4;
      renderStep(currentStep);
    }

    function togglePlay() {
      isPlaying = !isPlaying;
      document.getElementById('playBtn').textContent = isPlaying ? '⏸' : '▶';
      if (isPlaying) {
        startTimer();
      } else {
        clearInterval(timer);
      }
    }

    function startTimer() {
      clearInterval(timer);
      timer = setInterval(() => {
        nextStep();
      }, 3500);
    }

    // Initial Start
    renderStep(0);
    startTimer();
  </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;
    }

    body {
      width: 100%;
      background: transparent;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px 8px;
      user-select: none;
    }

    .main-container {
      width: 100%;
      max-width: 640px;
      display: flex;
      flex-direction: column;
      gap: 12px;
      align-items: center;
    }

    /* Section Header Tabs */
    .section-headers {
      display: flex;
      width: 100%;
      gap: 8px;
    }

    .section-tag {
      font-size: 11px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.05em;
      padding: 4px 8px;
      border-radius: 6px;
      text-align: center;
    }

    .tag-whole {
      flex: 2;
      background: #f1f5f9;
      color: #475569;
      border: 1px solid #cbd5e1;
    }

    .tag-sep {
      width: 18px;
    }

    .tag-decimal {
      flex: 3;
      background: #e0f2fe;
      color: #0369a1;
      border: 1px solid #7dd3fc;
    }

    /* Place Value Grid */
    .chart-grid {
      display: flex;
      width: 100%;
      align-items: stretch;
      gap: 4px;
    }

    .col-card {
      flex: 1;
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 8px 2px;
      gap: 6px;
      cursor: pointer;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    }

    .col-card.decimal-col {
      background: #f8fafc;
      border-color: #cbd5e1;
    }

    .col-card.active {
      border-color: #0284c7;
      background: #f0f9ff;
      box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.2);
    }

    .digit-box {
      font-size: 28px;
      font-weight: 800;
      color: #0f172a;
      line-height: 1;
      padding: 4px 0;
    }

    .decimal-col .digit-box {
      color: #0369a1;
    }

    .col-card.active .digit-box {
      color: #0284c7;
    }

    /* Decimal Point Separator */
    .decimal-point-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding-top: 14px;
      width: 18px;
      flex-shrink: 0;
    }

    .dot-glow {
      width: 12px;
      height: 12px;
      border-radius: 50%;
      background: #0284c7;
      box-shadow: 0 0 10px rgba(2, 132, 199, 0.7);
    }

    .place-name {
      font-size: 11px;
      font-weight: 700;
      color: #334155;
      text-align: center;
      line-height: 1.1;
    }

    .place-val {
      font-size: 10px;
      font-weight: 600;
      color: #64748b;
      background: #f1f5f9;
      padding: 2px 4px;
      border-radius: 4px;
      text-align: center;
    }

    .col-card.active .place-val {
      background: #e0f2fe;
      color: #0369a1;
    }

    .dp-badge {
      font-size: 9px;
      font-weight: 700;
      color: #0284c7;
      background: #e0f2fe;
      padding: 2px 4px;
      border-radius: 4px;
      text-align: center;
      white-space: nowrap;
    }

    /* Interactive Buttons */
    .btn-row {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 6px;
      width: 100%;
      margin-top: 4px;
    }

    .mode-btn {
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      color: #334155;
      padding: 6px 10px;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s, border-color 0.2s, color 0.2s;
    }

    .mode-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .mode-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
    }

    /* Responsive text adjustments */
    @media (min-width: 480px) {
      .digit-box { font-size: 34px; }
      .place-name { font-size: 12px; }
      .place-val { font-size: 11px; padding: 2px 6px; }
      .dp-badge { font-size: 10px; padding: 3px 6px; }
      .section-tag { font-size: 12px; }
      .mode-btn { font-size: 13px; padding: 6px 14px; }
    }
  </style>
</head>
<body>

  <div class="main-container">
    
    <div class="section-headers">
      <div class="section-tag tag-whole">Whole Part</div>
      <div class="tag-sep"></div>
      <div class="section-tag tag-decimal">Decimal Part</div>
    </div>

    
    <div class="chart-grid">
      
      <div class="col-card" id="card-0" onclick="selectCard(0)">
        <div class="digit-box">3</div>
        <div class="place-name">Tens</div>
        <div class="place-val">10</div>
      </div>

      
      <div class="col-card" id="card-1" onclick="selectCard(1)">
        <div class="digit-box">5</div>
        <div class="place-name">Ones</div>
        <div class="place-val">1</div>
      </div>

      
      <div class="decimal-point-col" title="Decimal Point">
        <div class="dot-glow"></div>
      </div>

      
      <div class="col-card decimal-col" id="card-2" onclick="selectCard(2)">
        <div class="digit-box">8</div>
        <div class="place-name">Tenths</div>
        <div class="place-val">0.1</div>
        <div class="dp-badge">1 d.p.</div>
      </div>

      
      <div class="col-card decimal-col" id="card-3" onclick="selectCard(3)">
        <div class="digit-box">4</div>
        <div class="place-name">Hundredths</div>
        <div class="place-val">0.01</div>
        <div class="dp-badge">2 d.p.</div>
      </div>

      
      <div class="col-card decimal-col" id="card-4" onclick="selectCard(4)">
        <div class="digit-box">7</div>
        <div class="place-name">Thousandths</div>
        <div class="place-val">0.001</div>
        <div class="dp-badge">3 d.p.</div>
      </div>
    </div>

    
    <div class="btn-row">
      <button class="mode-btn" id="btn-1" onclick="selectCard(1)">Ones (Whole)</button>
      <button class="mode-btn active" id="btn-2" onclick="selectCard(2)">1 d.p. (Tenths)</button>
      <button class="mode-btn" id="btn-3" onclick="selectCard(3)">2 d.p. (Hundredths)</button>
      <button class="mode-btn" id="btn-4" onclick="selectCard(4)">3 d.p. (Thousandths)</button>
    </div>
  </div>

  <script>
    function selectCard(idx) {
      // Update card active states
      for (let i = 0; i < 5; i++) {
        const card = document.getElementById('card-' + i);
        if (card) {
          if (i === idx) {
            card.classList.add('active');
          } else {
            card.classList.remove('active');
          }
        }
      }

      // Update button active states
      const btnMap = { 1: 'btn-1', 2: 'btn-2', 3: 'btn-3', 4: 'btn-4' };
      for (const key in btnMap) {
        const btn = document.getElementById(btnMap[key]);
        if (btn) {
          if (parseInt(key) === idx) {
            btn.classList.add('active');
          } else {
            btn.classList.remove('active');
          }
        }
      }
    }

    // Default select 1 d.p. (Tenths)
    selectCard(2);
  </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;
      user-select: none;
    }

    body {
      width: 100%;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 16px 12px;
    }

    .diagram-area {
      width: 100%;
      max-width: 580px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 16px;
    }

    svg {
      width: 100%;
      height: auto;
      overflow: visible;
    }

    .tick-label {
      font-size: 13px;
      fill: #64748b;
      text-anchor: middle;
      font-weight: 500;
    }

    .end-label {
      font-size: 16px;
      font-weight: 700;
      fill: #1e2945;
    }

    .halfway-label {
      font-size: 13px;
      font-weight: 700;
      fill: #d97706;
      text-anchor: middle;
    }

    .value-label {
      font-size: 15px;
      font-weight: 800;
      fill: #0284c7;
      text-anchor: middle;
    }

    .target-highlight {
      font-size: 15px;
      font-weight: 800;
      fill: #16a34a;
      text-anchor: middle;
    }

    /* Result pill */
    .result-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      background: #f0fdf4;
      border: 1.5px solid #86efac;
      color: #15803d;
      padding: 8px 18px;
      border-radius: 9999px;
      font-size: 16px;
      font-weight: 700;
      box-shadow: 0 2px 6px rgba(22, 163, 74, 0.1);
      transition: all 0.25s ease;
    }

    .check-icon {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 22px;
      height: 22px;
      background: #16a34a;
      color: #ffffff;
      border-radius: 50%;
      font-size: 13px;
    }

    /* Preset switcher */
    .presets {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
      justify-content: center;
    }

    .preset-btn {
      background: #f8fafc;
      border: 1px solid #cbd5e1;
      color: #475569;
      padding: 6px 14px;
      border-radius: 8px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      transition: all 0.2s ease;
    }

    .preset-btn:hover {
      background: #f1f5f9;
      border-color: #94a3b8;
    }

    .preset-btn.active {
      background: #0284c7;
      border-color: #0284c7;
      color: #ffffff;
      box-shadow: 0 2px 8px rgba(2, 132, 199, 0.25);
    }
  </style>
</head>
<body>

  <div class="diagram-area">
    
    <div class="presets">
      <button class="preset-btn" onclick="setValue(4.32)">4.32</button>
      <button class="preset-btn" onclick="setValue(4.35)">4.35 (Halfway)</button>
      <button class="preset-btn active" onclick="setValue(4.36)">4.36 (Example)</button>
      <button class="preset-btn" onclick="setValue(4.38)">4.38</button>
    </div>

    
    <svg viewBox="0 0 600 170" aria-label="Number line zooming in between 4.30 and 4.40">
      <defs>
        <marker id="arrow-right" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 0 1 L 8 5 L 0 9 z" fill="#16a34a" />
        </marker>
        <marker id="arrow-left" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 8 1 L 0 5 L 8 9 z" fill="#16a34a" />
        </marker>
      </defs>

      
      <line x1="50" y1="90" x2="550" y2="90" stroke="#cbd5e1" stroke-width="4" stroke-linecap="round" />

      
      
      <line x1="60" y1="72" x2="60" y2="108" stroke="#1e2945" stroke-width="3" stroke-linecap="round" />
      <text x="60" y="132" class="tick-label end-label">4.30</text>

      
      <line x1="108" y1="82" x2="108" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="108" y="112" class="tick-label">.31</text>

      <line x1="156" y1="82" x2="156" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="156" y="112" class="tick-label">.32</text>

      <line x1="204" y1="82" x2="204" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="204" y="112" class="tick-label">.33</text>

      <line x1="252" y1="82" x2="252" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="252" y="112" class="tick-label">.34</text>

      
      <line x1="300" y1="36" x2="300" y2="104" stroke="#f59e0b" stroke-width="2.5" stroke-dasharray="4,4" />
      <text x="300" y="26" class="halfway-label">4.35 (Halfway)</text>
      <text x="300" y="112" class="tick-label" style="fill:#d97706; font-weight:700;">.35</text>

      <line x1="348" y1="82" x2="348" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="348" y="112" class="tick-label">.36</text>

      <line x1="396" y1="82" x2="396" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="396" y="112" class="tick-label">.37</text>

      <line x1="444" y1="82" x2="444" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="444" y="112" class="tick-label">.38</text>

      <line x1="492" y1="82" x2="492" y2="98" stroke="#94a3b8" stroke-width="1.5" />
      <text x="492" y="112" class="tick-label">.39</text>

      
      <line x1="540" y1="72" x2="540" y2="108" stroke="#1e2945" stroke-width="3" stroke-linecap="round" />
      <text x="540" y="132" class="tick-label end-label">4.40</text>

      
      <path id="pull-arrow" d="M 348 70 Q 444 38 534 82" fill="none" stroke="#16a34a" stroke-width="2.5" stroke-dasharray="5,4" marker-end="url(#arrow-right)" />

      
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        <circle r="14" fill="rgba(2, 132, 199, 0.18)" />
        <circle r="7.5" fill="#0284c7" stroke="#ffffff" stroke-width="2" />
        <text id="active-text" y="-18" class="value-label">4.36</text>
      </g>
    </svg>

    
    <div id="result-badge" class="result-badge">
      <span class="check-icon">✓</span>
      <span id="result-text">Round up to 4.4</span>
    </div>
  </div>

  <script>
    function xForVal(val) {
      // 4.30 -> 60, 4.40 -> 540
      return 60 + ((val - 4.30) / 0.10) * 480;
    }

    function setValue(val) {
      // Update active button
      document.querySelectorAll('.preset-btn').forEach(btn => {
        btn.classList.toggle('active', btn.textContent.startsWith(val.toString()));
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      const x = xForVal(val);
      const activeGroup = document.getElementById('active-group');
      const activeText = document.getElementById('active-text');
      const pullArrow = document.getElementById('pull-arrow');
      const resultBadge = document.getElementById('result-badge');
      const resultText = document.getElementById('result-text');

      activeGroup.setAttribute('transform', `translate(${x}, 90)`);
      activeText.textContent = val.toFixed(2);

      if (val >= 4.35) {
        // Round up to 4.4
        const midX = (x + 540) / 2;
        pullArrow.setAttribute('d', `M ${x} 70 Q ${midX} 35 534 82`);
        pullArrow.setAttribute('marker-end', 'url(#arrow-right)');
        pullArrow.style.display = 'block';

        resultBadge.style.background = '#f0fdf4';
        resultBadge.style.borderColor = '#86efac';
        resultBadge.style.color = '#15803d';
        resultText.textContent = 'Round up to 4.4';
      } else {
        // Round down to 4.3
        const midX = (x + 60) / 2;
        pullArrow.setAttribute('d', `M ${x} 70 Q ${midX} 35 66 82`);
        pullArrow.setAttribute('marker-end', 'url(#arrow-left)');
        pullArrow.style.display = 'block';

        resultBadge.style.background = '#eff6ff';
        resultBadge.style.borderColor = '#93c5fd';
        resultBadge.style.color = '#1d4ed8';
        resultText.textContent = 'Round down to 4.3';
      }
    }
  </script>
</body>
</html>

Los números enteros en la vida cotidiana

Representación de enteros en la recta numérica

El opuesto de un número entero

Concepto de valor absoluto

Comparación y orden de enteros con la recta numérica

Ordenamiento de conjuntos de números enteros

Medidas relativas: temperatura y altitud

Distancia entre dos puntos en la recta numérica

Desigualdades simples con enteros en la recta

Resolución de problemas con medidas relativas de enteros

Razonabilidad de resultados con enteros y estimación

math

Números enteros: Concepto, orden y valor absoluto

Adición de enteros con el mismo signo

Adición de enteros con signos diferentes

Propiedades de la adición de enteros

Sustracción de enteros como suma del opuesto

Práctica fluida de sumas y restas de enteros

Multiplicación de enteros y regla de signos

Propiedades de la multiplicación en enteros

División exacta de números enteros

Operaciones combinadas con enteros y jerarquía

Resolución de problemas aditivos y multiplicativos con enteros

Uso de la calculadora para verificar operaciones con enteros

Operaciones con números enteros

Concepto de número racional y representación fraccionaria

Fracciones propias, impropias y números mixtos

Fracciones equivalentes por amplificación y simplificación

Fracción irreducible y simplificación máxima

Ubicación de fracciones positivas y negativas en la recta

Comparación de fracciones con distinto denominador

Densidad de los números racionales

Fracciones como operadores de cantidades y medidas

Problemas de comparación y medición con fracciones

Números racionales: Fracciones y equivalencia

Adición y sustracción de fracciones homogéneas

Adición y sustracción de fracciones heterogéneas con mcm

Suma y resta de números mixtos

Multiplicación de fracciones y modelo de área

Simplificación cruzada en la multiplicación de fracciones

Multiplicación con números mixtos y enteros

Adición, sustracción y multiplicación de fracciones y números mixtos

Rounding Decimals Using Number Lines

Rounding Decimals to a Given Accuracy

Rounding Decimals to Different Decimal Places

Estimating Calculations by Rounding

Checking Reasonableness of Solutions Using Estimation

Rounding in Real-World Contexts

Rounding Decimals and Estimation

Estructura posicional y descomposición polinomial decimal

Conversión entre fracciones y decimales exactos

Decimales periódicos puros y mixtos

Comparación y orden de números decimales en la recta

Redondeo y truncamiento de números decimales

Representación y propiedades de los números decimales

Identifying and Counting Significant Figures

Rounding Measurements and Values to Significant Figures

Estimating Calculations and Assessing Result Reasonableness

Converting Large Numbers to and from Scientific Notation

Converting Small Decimals to and from Scientific Notation

Multiplying and Dividing Numbers in Scientific Notation

Adding and Subtracting Numbers in Scientific Notation

Comparing Magnitudes and Scientific Notation Word Problems

Estimation, Significant Figures, and Scientific Notation

Adición y sustracción alineada de decimales

Multiplicación de números decimales

Multiplicación y división de decimales por potencias de 10

División de decimales entre enteros

División entre números decimales

Problemas contextuales con decimales y dinero

Estimación frente a cálculo exacto con decimales

Operaciones y problemas con números decimales

Multi-Step Problems with Rational Numbers

Mixed Operations with Rational Numbers: Real-World Problems

Multi-Step Real-World Problems with Fractions, Decimals, and Percents

Modelling Real-World Problems with Rational Numbers

Evaluating Precision and Error in Multi-Step Measurements

Applied Problem Solving with Rational and Real Numbers

Raíces cuadradas exactas y estimadas

Raíces cúbicas exactas

Propiedades de la radicación: raíz de un producto y cociente

Orden de operaciones con potencias y raíces

Notación científica introductoria y grandes números

Resolución de problemas de crecimiento exponencial y geométrico

Radicación, operaciones combinadas y aplicaciones

夹逼法估算无理数的整数区间

逐步逼近法估算无理数的十分位与百分位

近似数的概念、精确度与四舍五入规则

利用计算器进行实际问题中的近似计算

无理数估算与近似数计算

Múltiplos y divisores de un número natural

Criterios de divisibilidad por 2, 3, 5 y 10

Criterios de divisibilidad por 4, 6, 9 y 11

Números primos, compuestos y la criba de Eratóstenes

Descomposición en factores primos: árbol y división sucesiva

Cálculo del máximo común divisor (MCD)

Cálculo del mínimo común múltiplo (mcm)

Resolución de problemas verbales con MCD

Resolución de problemas verbales con mcm

Teoría de números: Divisibilidad, MCD y mcm

Concepto de razón y formas de representación

Razones equivalentes y tablas de razón

Concepto de tasa y tasa unitaria

Comparación de precios unitarios para la mejor compra

Concepto de proporcionalidad directa y constante k

Ecuaciones de proporcionalidad directa: y = kx

Gráficas de proporcionalidad directa en el plano

Regla de tres simple directa

Problemas de velocidad constante, distancia y tiempo

Factores de conversión unitarios con proporcionalidad

Razones, tasas y proporcionalidad directa

Concepto de proporcionalidad inversa

Tablas y gráficas de proporcionalidad inversa

Regla de tres simple inversa

Comparación entre proporcionalidad directa e inversa

Concepto de porcentaje y equivalencias fracción-decimal

Cálculo del porcentaje de una cantidad

Hallar la cantidad total a partir de un porcentaje

Porcentaje de aumento y descuento comercial

Cálculo de impuestos (IVA) y propinas

Interés simple: fórmula y aplicaciones

Variación porcentual: incremento y decremento

Proporcionalidad inversa, porcentajes y finanzas

同底数幂的乘法与幂的乘方运算性质

积的乘方与同底数幂的除法运算性质

零指数幂与负整数指数幂的拓展与运算

科学记数法表示大数与计算器中的科学记数显示

科学记数法表示微小量与纳米级单位换算

整数指数幂与科学记数法

Perímetro de polígonos regulares e irregulares

Área de rectángulos, paralelogramos y cuadrados

Área de triángulos y su justificación geométrica

Área de trapecios y rombos

Área de polígonos regulares: apotema y perímetro

Elementos del círculo y la circunferencia

El número pi y la longitud de la circunferencia

Área del círculo y justificación por sectores

Área de figuras compuestas por adición y sustracción

Resolución de problemas reales de áreas y costos de materiales

Perímetro, área y geometría del círculo

Sistema Internacional de Unidades y prefijos métricos

Conversión de unidades de longitud y distancia

Conversión de unidades de superficie y área

Conversión de unidades de volumen y capacidad

Conversión de unidades de masa y peso

Unidades de tiempo y cálculo de intervalos

Técnicas de estimación de longitudes y distancias

Estimación de áreas irregulares mediante cuadrículas

Estimación de masas, capacidades y cantidades discontinuas

Análisis de variaciones en las medidas y margen de error

Magnitudes, unidades de medida y estimación

Listas sistemáticas y tablas de doble entrada para conteo

Diagramas de árbol para conteo

Principio fundamental del conteo: regla del producto

Permutaciones simples: orden en las agrupaciones

Combinaciones simples: cuando el orden no importa

Resolución de problemas combinatorios en contextos cotidianos

Exploración de patrones numéricos con calculadora

Conjeturas sobre divisibilidad y primos usando tecnología

Elección del método de cálculo: mental, escrito o digital

Conteo combinatorio y herramientas tecnológicas

OGM.8.NO.6

OGM.8.NO.6

Aligned learning resources

Related diagrams