<!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 {
      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;
    }

    .diagram-area {
      width: 100%;
      max-width: 620px;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    svg {
      width: 100%;
      height: auto;
      overflow: visible;
      user-select: none;
    }

    /* SVG Elements Styling */
    .digit {
      font-family: "SF Mono", "Courier New", Courier, monospace;
      font-size: 38px;
      font-weight: 700;
      fill: #1e2945;
      text-anchor: middle;
      dominant-baseline: middle;
    }

    .digit-faded {
      fill: #cbd5e1;
    }

    .hop-path {
      fill: none;
      stroke: #0284c7;
      stroke-width: 2.5;
      stroke-linecap: round;
      stroke-dasharray: 120;
      stroke-dashoffset: 0;
      transition: stroke-dashoffset 0.4s ease, opacity 0.3s ease;
    }

    .hop-badge-bg {
      fill: #0284c7;
      transition: fill 0.2s, opacity 0.3s;
    }

    .hop-badge-text {
      font-size: 13px;
      font-weight: 700;
      fill: #ffffff;
      text-anchor: middle;
      dominant-baseline: central;
      font-family: system-ui, sans-serif;
    }

    .hop-group {
      opacity: 0.18;
      transition: opacity 0.35s ease;
    }

    .hop-group.active {
      opacity: 1;
    }

    .dot-marker {
      fill: #ef4444;
      transition: cx 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
    }

    .new-dot-marker {
      fill: #0284c7;
      opacity: 0;
      transition: opacity 0.3s;
    }

    .new-dot-marker.visible {
      opacity: 1;
    }

    /* Result Row */
    .result-section {
      width: 100%;
      max-width: 540px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
      margin-top: -8px;
    }

    .arrow-down {
      font-size: 20px;
      color: #94a3b8;
      line-height: 1;
    }

    .result-card {
      display: flex;
      align-items: baseline;
      justify-content: center;
      gap: 10px;
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 18px;
      font-family: "SF Mono", monospace;
      font-size: 24px;
      font-weight: 700;
      color: #1e2945;
    }

    .exp-badge {
      background: #e0f2fe;
      color: #0284c7;
      padding: 2px 8px;
      border-radius: 6px;
      border: 1px solid #bae6fd;
      font-size: 22px;
    }

    .caption-pill {
      background: #f0fdf4;
      color: #166534;
      border: 1px solid #bbf7d0;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 14px;
      font-weight: 600;
      text-align: center;
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      margin-top: 8px;
      flex-wrap: wrap;
    }

    .btn {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #334155;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      user-select: none;
    }

    .btn:active {
      background: #e2e8f0;
    }

    .step-btn {
      width: 28px;
      height: 28px;
      padding: 0;
      justify-content: center;
      border-radius: 50%;
      font-size: 12px;
    }

    .step-btn.active {
      background: #0284c7;
      color: #fff;
      border-color: #0284c7;
    }
  </style>
</head>
<body>

  <div class="diagram-area">
    <svg viewBox="0 0 620 220" aria-label="Decimal hop diagram for 54,600,000">
      <defs>
        
        <marker id="arrow" viewBox="0 0 10 10" refX="2" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
          <path d="M 10 1 L 0 5 L 10 9 z" fill="#0284c7" />
        </marker>
      </defs>

      
      
      <g id="hop-1" class="hop-group active">
        <path d="M 580 94 A 32 30 0 0 0 516 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="548" cy="50" r="11" class="hop-badge-bg" />
        <text x="548" y="50" class="hop-badge-text">1</text>
      </g>

      
      <g id="hop-2" class="hop-group active">
        <path d="M 516 94 A 32 30 0 0 0 452 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="484" cy="50" r="11" class="hop-badge-bg" />
        <text x="484" y="50" class="hop-badge-text">2</text>
      </g>

      
      <g id="hop-3" class="hop-group active">
        <path d="M 452 94 A 32 30 0 0 0 388 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="420" cy="50" r="11" class="hop-badge-bg" />
        <text x="420" y="50" class="hop-badge-text">3</text>
      </g>

      
      <g id="hop-4" class="hop-group active">
        <path d="M 388 94 A 32 30 0 0 0 324 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="356" cy="50" r="11" class="hop-badge-bg" />
        <text x="356" y="50" class="hop-badge-text">4</text>
      </g>

      
      <g id="hop-5" class="hop-group active">
        <path d="M 324 94 A 32 30 0 0 0 260 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="292" cy="50" r="11" class="hop-badge-bg" />
        <text x="292" y="50" class="hop-badge-text">5</text>
      </g>

      
      <g id="hop-6" class="hop-group active">
        <path d="M 260 94 A 32 30 0 0 0 196 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="228" cy="50" r="11" class="hop-badge-bg" />
        <text x="228" y="50" class="hop-badge-text">6</text>
      </g>

      
      <g id="hop-7" class="hop-group active">
        <path d="M 196 94 A 32 30 0 0 0 132 94" class="hop-path" marker-end="url(#arrow)" />
        <circle cx="164" cy="50" r="11" class="hop-badge-bg" />
        <text x="164" y="50" class="hop-badge-text">7</text>
      </g>

      
      
      <text x="100" y="112" class="digit">5</text>
      <text x="164" y="112" class="digit">4</text>
      <text x="228" y="112" class="digit">6</text>
      <text x="292" y="112" class="digit">0</text>
      <text x="356" y="112" class="digit">0</text>
      <text x="420" y="112" class="digit">0</text>
      <text x="484" y="112" class="digit">0</text>
      <text x="548" y="112" class="digit">0</text>

      
      <circle id="movingDot" cx="132" cy="116" r="4.5" class="dot-marker" />

      
      
      <text x="100" y="182" class="digit">5</text>
      <circle cx="132" cy="186" r="4.5" fill="#0284c7" />
      <text x="164" y="182" class="digit">4</text>
      <text x="228" y="182" class="digit">6</text>
      <text x="292" y="182" class="digit digit-faded">0</text>
      <text x="356" y="182" class="digit digit-faded">0</text>
      <text x="420" y="182" class="digit digit-faded">0</text>
      <text x="484" y="182" class="digit digit-faded">0</text>
      <text x="548" y="182" class="digit digit-faded">0</text>
    </svg>
  </div>

  
  <div class="result-section">
    <div class="arrow-down">↓</div>
    <div class="result-card">
      <span id="sigFigs">5.46</span>
      <span>×</span>
      <span class="exp-badge" id="expLabel">10⁷</span>
    </div>
    <div class="caption-pill">
      7 hops left = exponent of 10 is +7
    </div>
  </div>

  
  <div class="controls">
    <button class="btn" id="playBtn" onclick="togglePlay()">⏸ Pause</button>
    <button class="btn step-btn" onclick="setStep(1)">1</button>
    <button class="btn step-btn" onclick="setStep(2)">2</button>
    <button class="btn step-btn" onclick="setStep(3)">3</button>
    <button class="btn step-btn" onclick="setStep(4)">4</button>
    <button class="btn step-btn" onclick="setStep(5)">5</button>
    <button class="btn step-btn" onclick="setStep(6)">6</button>
    <button class="btn step-btn active" onclick="setStep(7)">7</button>
  </div>

  <script>
    const dotPositions = [580, 516, 452, 388, 324, 260, 196, 132];
    let currentStep = 7;
    let isPlaying = true;
    let timer = null;

    function renderStep(step) {
      currentStep = step;
      // Update hops visibility
      for (let i = 1; i <= 7; i++) {
        const hop = document.getElementById(`hop-${i}`);
        if (hop) {
          hop.classList.toggle('active', i <= step);
        }
      }

      // Update dot position
      const dot = document.getElementById('movingDot');
      if (dot) {
        dot.setAttribute('cx', dotPositions[step]);
      }

      // Update exponent badge
      const expLabel = document.getElementById('expLabel');
      const superscripts = ['⁰', '¹', '²', '³', '⁴', '⁵', '⁶', '⁷'];
      if (expLabel) {
        expLabel.textContent = `10${superscripts[step] || '⁷'}`;
      }

      // Update step buttons
      const buttons = document.querySelectorAll('.step-btn');
      buttons.forEach((btn, idx) => {
        btn.classList.toggle('active', idx + 1 === step);
      });
    }

    function setStep(step) {
      pause();
      renderStep(step);
    }

    function nextStep() {
      let next = currentStep + 1;
      if (next > 7) next = 1;
      renderStep(next);
    }

    function play() {
      isPlaying = true;
      document.getElementById('playBtn').textContent = '⏸ Pause';
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 1500);
    }

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

    function togglePlay() {
      if (isPlaying) {
        pause();
      } else {
        play();
      }
    }

    // Initialize
    renderStep(7);
    play();
  </script>
</body>
</html>

Writing Large Numbers Using Powers of 10

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: transparent;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 8px 4px;
      gap: 10px;
    }

    .header {
      text-align: center;
      width: 100%;
    }
    .main-expr {
      font-size: 22px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      justify-content: center;
      flex-wrap: wrap;
      gap: 6px;
    }
    .power-badge {
      display: inline-flex;
      align-items: center;
      background: #0d9488;
      color: #ffffff;
      padding: 2px 10px;
      border-radius: 12px;
      font-size: 12px;
      font-weight: 600;
    }

    /* Diagram Canvas */
    .stage {
      width: 100%;
      max-width: 500px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }

    /* Digit & Hop Display */
    .visual-board {
      width: 100%;
      position: relative;
      display: flex;
      flex-direction: column;
      align-items: center;
    }

    .svg-hops {
      width: 100%;
      max-width: 440px;
      height: 46px;
      overflow: visible;
    }

    .hop-path {
      fill: none;
      stroke: #cbd5e1;
      stroke-width: 2.5;
      stroke-linecap: round;
      transition: stroke 0.3s ease, stroke-width 0.3s ease;
    }
    .hop-path.active-hop {
      stroke: #0d9488;
      stroke-width: 3.5;
    }
    .hop-path.zero-hop {
      stroke: #ea580c;
      stroke-width: 3.5;
    }

    .hop-label {
      font-size: 11px;
      font-weight: 700;
      fill: #64748b;
      text-anchor: middle;
      transition: fill 0.3s ease;
    }
    .hop-label.active-label {
      fill: #0f766e;
    }
    .hop-label.zero-label {
      fill: #c2410c;
    }

    .digits-row {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 3px;
      width: 100%;
      max-width: 440px;
      margin-top: -2px;
    }

    .digit-cell {
      flex: 1;
      max-width: 44px;
      height: 46px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 20px;
      font-weight: 700;
      border-radius: 8px;
      background: #f1f5f9;
      color: #0f172a;
      transition: all 0.3s ease;
      position: relative;
    }

    .digit-cell.dot-cell {
      flex: 0 0 14px;
      max-width: 14px;
      background: transparent;
      font-size: 26px;
      color: #94a3b8;
      margin-top: -6px;
    }
    .digit-cell.dot-cell.shifted {
      color: transparent;
    }

    .digit-cell.existing {
      background: #e2e8f0;
      color: #1e293b;
    }
    .digit-cell.hop-passed {
      background: #ccfbf1;
      color: #0f766e;
      box-shadow: 0 0 0 2px #14b8a6;
    }

    .digit-cell.placeholder-zero {
      background: #fff7ed;
      color: #ea580c;
      box-shadow: 0 0 0 2px #f97316;
      font-weight: 800;
    }
    .digit-cell.empty-slot {
      border: 2px dashed #cbd5e1;
      background: transparent;
      color: #cbd5e1;
    }

    /* Result callout */
    .result-banner {
      width: 100%;
      padding: 8px 12px;
      border-radius: 10px;
      background: #f8fafc;
      border: 1px solid #e2e8f0;
      display: flex;
      align-items: center;
      justify-content: space-between;
      min-height: 44px;
      gap: 8px;
    }
    .result-text {
      font-size: 17px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: 0.5px;
    }
    .highlight-pill {
      font-size: 11px;
      font-weight: 600;
      padding: 3px 8px;
      border-radius: 6px;
      background: #e0f2fe;
      color: #0369a1;
      text-align: right;
    }
    .highlight-pill.warn {
      background: #ffedd5;
      color: #c2410c;
    }

    .key-note {
      font-size: 11.5px;
      color: #64748b;
      text-align: center;
      line-height: 1.4;
      max-width: 480px;
    }
    .key-note strong {
      color: #c2410c;
    }

    /* Controls */
    .controls {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
      width: 100%;
      max-width: 440px;
    }
    .step-buttons {
      display: flex;
      gap: 6px;
      width: 100%;
      justify-content: center;
    }
    .step-btn {
      flex: 1;
      padding: 6px 0;
      border-radius: 8px;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      color: #475569;
      font-size: 12px;
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s, color 0.2s, border-color 0.2s;
    }
    .step-btn:hover {
      background: #f1f5f9;
    }
    .step-btn.active {
      background: #0f172a;
      color: #ffffff;
      border-color: #0f172a;
    }

    .playback-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
    }
    .play-btn {
      border: none;
      background: #0d9488;
      color: #ffffff;
      width: 30px;
      height: 30px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 12px;
      cursor: pointer;
      transition: background 0.2s;
    }
    .play-btn:hover {
      background: #0f766e;
    }

    .dots-container {
      display: flex;
      gap: 6px;
    }
    .dot {
      width: 9px;
      height: 9px;
      border-radius: 50%;
      background: #cbd5e1;
      cursor: pointer;
      border: none;
      padding: 0;
      transition: background 0.2s;
    }
    .dot.active {
      background: #0d9488;
    }

    @media (max-width: 400px) {
      .main-expr {
        font-size: 19px;
      }
      .digit-cell {
        height: 40px;
        font-size: 18px;
      }
      .digit-cell.dot-cell {
        font-size: 22px;
      }
      .result-text {
        font-size: 15px;
      }
      .highlight-pill {
        font-size: 10px;
      }
    }
  </style>
</head>
<body>

  <div class="header">
    <div class="main-expr">
      <span>7.09 × 10<sup style="font-size: 14px;">6</sup></span>
      <span class="power-badge">6 Places Right</span>
    </div>
  </div>

  <div class="stage">
    
    <div class="visual-board">
      <svg class="svg-hops" viewBox="0 0 360 40">
        
        <g id="hop-1">
          <path class="hop-path" d="M 35 34 Q 60 2, 85 34" />
          <text class="hop-label" x="60" y="16">1</text>
        </g>
        <g id="hop-2">
          <path class="hop-path" d="M 85 34 Q 110 2, 135 34" />
          <text class="hop-label" x="110" y="16">2</text>
        </g>
        <g id="hop-3">
          <path class="hop-path" d="M 135 34 Q 160 2, 185 34" />
          <text class="hop-label" x="160" y="16">3</text>
        </g>
        <g id="hop-4">
          <path class="hop-path" d="M 185 34 Q 210 2, 235 34" />
          <text class="hop-label" x="210" y="16">4</text>
        </g>
        <g id="hop-5">
          <path class="hop-path" d="M 235 34 Q 260 2, 285 34" />
          <text class="hop-label" x="260" y="16">5</text>
        </g>
        <g id="hop-6">
          <path class="hop-path" d="M 285 34 Q 310 2, 335 34" />
          <text class="hop-label" x="310" y="16">6</text>
        </g>
      </svg>

      <div class="digits-row">
        <div class="digit-cell existing">7</div>
        <div class="digit-cell dot-cell" id="origDot">.</div>
        <div class="digit-cell" id="cell-0">0</div>
        <div class="digit-cell" id="cell-9">9</div>
        <div class="digit-cell" id="cell-z1">0</div>
        <div class="digit-cell" id="cell-z2">0</div>
        <div class="digit-cell" id="cell-z3">0</div>
        <div class="digit-cell" id="cell-z4">0</div>
      </div>
    </div>

    
    <div class="result-banner">
      <span class="result-text" id="standardDisplay">7.09</span>
      <span class="highlight-pill" id="stepPill">6 hops planned</span>
    </div>

    <div class="key-note">
      💡 <strong>Note:</strong> Exponent 6 does <em>NOT</em> mean add 6 zeros — it means shift the decimal 6 places!
    </div>
  </div>

  
  <div class="controls">
    <div class="step-buttons">
      <button class="step-btn active" onclick="selectStep(0)">Step 1</button>
      <button class="step-btn" onclick="selectStep(1)">Step 2</button>
      <button class="step-btn" onclick="selectStep(2)">Step 3</button>
      <button class="step-btn" onclick="selectStep(3)">Step 4</button>
    </div>

    <div class="playback-bar">
      <button class="play-btn" id="playToggle" onclick="toggleAutoPlay()" title="Play/Pause">⏸</button>
      <div class="dots-container">
        <button class="dot active" onclick="selectStep(0)" aria-label="Step 1"></button>
        <button class="dot" onclick="selectStep(1)" aria-label="Step 2"></button>
        <button class="dot" onclick="selectStep(2)" aria-label="Step 3"></button>
        <button class="dot" onclick="selectStep(3)" aria-label="Step 4"></button>
      </div>
    </div>
  </div>

  <script>
    let currentStep = 0;
    let autoPlayInterval = null;

    const stepsData = [
      {
        display: "7.09",
        pillText: "Exponent 6 → 6 hops right",
        pillClass: "highlight-pill",
        dotShifted: false,
        hops: [1, 1, 1, 1, 1, 1], // 1 = active teal, 2 = zero orange, 0 = dim
        cell0: "existing",
        cell9: "existing",
        z1: "empty", z2: "empty", z3: "empty", z4: "empty"
      },
      {
        display: "709",
        pillText: "2 hops pass existing digits (0, 9)",
        pillClass: "highlight-pill",
        dotShifted: true,
        hops: [1, 1, 0, 0, 0, 0],
        cell0: "passed",
        cell9: "passed",
        z1: "empty", z2: "empty", z3: "empty", z4: "empty"
      },
      {
        display: "709 0000",
        pillText: "4 remaining hops fill 4 placeholder zeros",
        pillClass: "highlight-pill warn",
        dotShifted: true,
        hops: [1, 1, 2, 2, 2, 2],
        cell0: "passed",
        cell9: "passed",
        z1: "fill", z2: "fill", z3: "fill", z4: "fill"
      },
      {
        display: "7,090,000",
        pillText: "Standard form with commas",
        pillClass: "highlight-pill warn",
        dotShifted: true,
        hops: [1, 1, 2, 2, 2, 2],
        cell0: "passed",
        cell9: "passed",
        z1: "fill", z2: "fill", z3: "fill", z4: "fill"
      }
    ];

    function renderStep(idx) {
      const data = stepsData[idx];

      // Update Result text & pill
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    renderStep(0);
    autoPlayInterval = setInterval(nextStep, 3500);
  </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">
  <title>Scientific Notation Anatomy</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
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    body {
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      color: #1e2945;
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      display: flex;
      flex-direction: column;
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    .header-badge {
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      align-items: center;
      gap: 6px;
      background: #f1f5f9;
      color: #475569;
      font-size: 13px;
      font-weight: 700;
      padding: 4px 12px;
      border-radius: 20px;
      letter-spacing: 0.2px;
    }

    .header-badge span {
      color: #0284c7;
      font-family: "Courier New", Courier, monospace;
      font-size: 14px;
    }

    /* Equation Breakdown Area */
    .anatomy-stage {
      display: flex;
      flex-direction: column;
      align-items: center;
      width: 100%;
      max-width: 480px;
      margin: 8px 0;
    }

    .expression-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 38px;
      font-weight: 800;
      line-height: 1;
      margin: 12px 0 6px;
    }

    .part-box {
      border-radius: 8px;
      padding: 4px 8px;
      cursor: pointer;
      transition: box-shadow 0.2s ease, background 0.2s ease;
      display: inline-flex;
      align-items: baseline;
    }

    .coeff-box {
      color: #0284c7;
      background: #e0f2fe;
      border: 2px solid #22b7ff;
    }
    .coeff-box.active {
      box-shadow: 0 0 0 3px rgba(34, 183, 255, 0.4);
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    .times-sign {
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      font-size: 28px;
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    .base-box {
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      background: #1e2945;
      border: 2px solid #1e2945;
    }
    .base-box.active {
      box-shadow: 0 0 0 3px rgba(30, 41, 69, 0.3);
    }

    .exp-wrapper {
      position: relative;
      top: -16px;
      margin-left: -4px;
    }

    .exp-box {
      font-size: 24px;
      color: #dc2626;
      background: #ffe4e6;
      border: 2px solid #ff6b6b;
      padding: 2px 6px;
    }
    .exp-box.active {
      box-shadow: 0 0 0 3px rgba(255, 107, 107, 0.4);
      background: #fecdd3;
    }

    /* Callout labels grid */
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      display: grid;
      grid-template-columns: 1.2fr 0.9fr 1.1fr;
      gap: 6px;
      width: 100%;
      margin-top: 6px;
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    .callout-tag {
      padding: 6px 4px;
      border-radius: 8px;
      text-align: center;
      font-size: 11px;
      cursor: pointer;
      transition: background 0.2s ease;
    }

    .callout-coeff {
      border-top: 3px solid #22b7ff;
      background: #f0f9ff;
    }
    .callout-base {
      border-top: 3px solid #1e2945;
      background: #f8fafc;
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    .callout-exp {
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    }

    .tag-title {
      font-weight: 700;
      font-size: 12px;
      display: block;
      margin-bottom: 2px;
    }
    .callout-coeff .tag-title { color: #0284c7; }
    .callout-base .tag-title { color: #1e2945; }
    .callout-exp .tag-title { color: #e11d48; }

    .tag-rule {
      color: #64748b;
      font-size: 10.5px;
      font-weight: 600;
      line-height: 1.2;
    }

    /* Quick Checks Section */
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      width: 100%;
      max-width: 480px;
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      flex-direction: column;
      gap: 6px;
    }

    .checks-title {
      font-size: 11px;
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      font-weight: 700;
      color: #1e2945;
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      align-items: center;
      gap: 3px;
      font-size: 11px;
      font-weight: 700;
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    .invalid .check-badge { color: #dc2626; }

    .check-reason {
      font-size: 9.5px;
      font-weight: 600;
      color: #64748b;
    }
  </style>
</head>
<body>

  
  <div class="header-badge">
    Standard Form: <span>a × 10<sup>b</sup></span>
  </div>

  
  <div class="anatomy-stage">
    <div class="expression-row">
      <div id="coeffEl" class="part-box coeff-box active" onclick="focusPart('coeff')">3.84</div>
      <span class="times-sign">×</span>
      <div id="baseEl" class="part-box base-box" onclick="focusPart('base')">10</div>
      <div class="exp-wrapper">
        <div id="expEl" class="part-box exp-box" onclick="focusPart('exp')">8</div>
      </div>
    </div>

    
    <div class="labels-grid">
      <div id="calloutCoeff" class="callout-tag callout-coeff" onclick="focusPart('coeff')">
        <span class="tag-title">Coefficient (a)</span>
        <span class="tag-rule">1 ≤ a &lt; 10</span>
      </div>

      <div id="calloutBase" class="callout-tag callout-base" onclick="focusPart('base')">
        <span class="tag-title">Base 10</span>
        <span class="tag-rule">Fixed system</span>
      </div>

      <div id="calloutExp" class="callout-tag callout-exp" onclick="focusPart('exp')">
        <span class="tag-title">Exponent (b)</span>
        <span class="tag-rule">Place shifts</span>
      </div>
    </div>
  </div>

  
  <div class="checks-section">
    <div class="checks-title">Validity Check</div>
    <div class="checks-row">
      <div class="check-card valid">
        <div class="check-expr">3.84 × 10<sup>8</sup></div>
        <div class="check-badge">✓ Valid</div>
        <div class="check-reason">1 ≤ 3.84 &lt; 10</div>
      </div>

      <div class="check-card invalid">
        <div class="check-expr">38.4 × 10<sup>7</sup></div>
        <div class="check-badge">✗ Invalid</div>
        <div class="check-reason">38.4 ≥ 10</div>
      </div>

      <div class="check-card invalid">
        <div class="check-expr">0.384 × 10<sup>9</sup></div>
        <div class="check-badge">✗ Invalid</div>
        <div class="check-reason">0.384 &lt; 1</div>
      </div>
    </div>
  </div>

  <script>
    function focusPart(type) {
      const coeff = document.getElementById('coeffEl');
      const base = document.getElementById('baseEl');
      const exp = document.getElementById('expEl');

      coeff.classList.remove('active');
      base.classList.remove('active');
      exp.classList.remove('active');

      if (type === 'coeff') coeff.classList.add('active');
      if (type === 'base') base.classList.add('active');
      if (type === 'exp') exp.classList.add('active');
    }
  </script>
</body>
</html>

OGM.9.NS.5

Aligned learning resources

Related diagrams