Advanced

Tutor model

i62 💰:9.4

i52 💰:7.9

🏆 i67 💰:62.5

i70 💰:125.0

i68 💰:125.0

🏆 i66 💰:75.0

i65 💰:125.0

i63 💰:62.5

i61 💰:75.0

i60 💰:9.4

i60 💰:37.5

i58 💰:62.5

i57 💰:22.5

i57 💰:37.5

i56 💰:45.0

⚡ i55 💰:11.25

i55 💰:37.5

i54 💰:62.5

i52 💰:35.0

i51 💰:37.5

i49 💰:15.0

i49 💰:62.5

i48 💰:11.3

i47 💰:7.5

i44 💰:25.0

i43 💰:37.5

i42 💰:187.5

i40 💰:5.0

i39 💰:100.0

i38 💰:37.5

i37 💰:11.0

i36 💰:187.5

i34 💰:12.5

i33 💰:37.5

i30 💰:1.0

i29 💰:1.5

i28 💰:150.0

i23 💰:20.0

i20 💰:4.0

i18 💰:1.0

i16 💰:25.0

i13 💰:1.5

Keep session private

What would you like to learn?

Override for the tutor's lesson content generation calls. Auto uses the system default (Claude Sonnet 5 for lesson text, Opus 5 for diagrams).

Lesson generation model

System default

i58 💰:18.8

i31 💰:11.0

i25 💰:31.3

Tutoring abilities

Imagine you have 4 sweet strawberries on a plate. You eat 1 strawberry for a snack!

When you remove items from a group, you are **taking away**. Let's see how many are left.

<!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 {
      background: #f8f9fa;
      color: #1e2945;
      padding: 16px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    /* Controls bar */
    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 12px;
    }

    .step-btn {
      background: #ffffff;
      border: 2px solid #e6e6e6;
      border-radius: 20px;
      padding: 6px 14px;
      font-size: 14px;
      font-weight: 600;
      color: #6b7280;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 6px;
      transition: all 0.25s ease;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
    }

    .step-btn.active {
      background: #ff4d6d;
      border-color: #ff4d6d;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(255, 77, 109, 0.3);
    }

    .play-btn {
      background: #ffffff;
      border: 2px solid #e6e6e6;
      border-radius: 50%;
      width: 34px;
      height: 34px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 14px;
      cursor: pointer;
      color: #1e2945;
      transition: all 0.2s ease;
    }

    /* Main stage */
    .stage {
      width: 100%;
      max-width: 480px;
      background: #ffffff;
      border-radius: 16px;
      padding: 20px 16px;
      box-shadow: 0 4px 16px rgba(0,0,0,0.04);
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 16px;
      position: relative;
    }

    .stage-title {
      font-size: 16px;
      font-weight: 700;
      color: #1e2945;
      height: 24px;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    /* Items grid */
    .grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 10px;
      width: 100%;
      padding: 6px 0;
    }

    .item-card {
      background: #f8f9fa;
      border-radius: 14px;
      border: 2px solid #eef0f3;
      padding: 12px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 6px;
      position: relative;
      transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    }

    .emoji {
      font-size: 38px;
      line-height: 1;
      transition: transform 0.4s ease, opacity 0.4s ease, filter 0.4s ease;
    }

    .num-badge {
      width: 22px;
      height: 22px;
      border-radius: 50%;
      background: #e2e8f0;
      color: #475569;
      font-size: 12px;
      font-weight: 700;
      display: flex;
      align-items: center;
      justify-content: center;
      transition: all 0.3s ease;
    }

    /* Step states */
    /* Step 1: Start 4 */
    .step-1 .item-card {
      border-color: #ffd6df;
      background: #fff5f7;
    }
    .step-1 .num-badge {
      background: #ff4d6d;
      color: #ffffff;
    }

    /* Step 2: Take away 1 */
    .step-2 .item-card:nth-child(-n+3) {
      border-color: #ffd6df;
      background: #fff5f7;
    }
    .step-2 .item-card:nth-child(-n+3) .num-badge {
      background: #ff4d6d;
      color: #ffffff;
    }
    .step-2 .item-card:nth-child(4) {
      border-color: #fca5a5;
      background: #fef2f2;
      border-style: dashed;
      transform: translateY(-4px);
    }
    .step-2 .item-card:nth-child(4) .emoji {
      opacity: 0.5;
      filter: grayscale(40%);
    }
    .step-2 .item-card:nth-child(4) .num-badge {
      background: #ef4444;
      color: #ffffff;
    }

    /* Step 3: Left 3 */
    .step-3 .item-card:nth-child(-n+3) {
      border-color: #a7f3d0;
      background: #f0fdf4;
      box-shadow: 0 4px 8px rgba(46, 196, 182, 0.15);
    }
    .step-3 .item-card:nth-child(-n+3) .num-badge {
      background: #2ec4b6;
      color: #ffffff;
    }
    .step-3 .item-card:nth-child(4) {
      border-color: #e2e8f0;
      background: #f8fafc;
      opacity: 0.25;
      transform: scale(0.92);
    }
    .step-3 .item-card:nth-child(4) .emoji {
      filter: grayscale(100%);
    }
    .step-3 .item-card:nth-child(4) .num-badge {
      background: #94a3b8;
      color: #ffffff;
    }

    /* Removal tag */
    .removal-tag {
      position: absolute;
      top: -8px;
      right: -6px;
      background: #ef4444;
      color: #ffffff;
      font-size: 11px;
      font-weight: 800;
      padding: 2px 6px;
      border-radius: 10px;
      display: none;
      box-shadow: 0 2px 4px rgba(239, 68, 68, 0.3);
    }

    .step-2 .item-card:nth-child(4) .removal-tag {
      display: block;
      animation: popIn 0.3s ease;
    }

    @keyframes popIn {
      0% { transform: scale(0.6); opacity: 0; }
      100% { transform: scale(1); opacity: 1; }
    }

    /* Equation display */
    .equation-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      padding: 8px 16px;
      background: #f8fafc;
      border-radius: 12px;
      font-size: 20px;
      font-weight: 800;
      color: #1e2945;
      width: 100%;
    }

    .eq-part {
      padding: 4px 10px;
      border-radius: 8px;
      transition: all 0.3s ease;
    }

    .eq-start.active { background: #ffe4e8; color: #ff4d6d; }
    .eq-minus.active { background: #fee2e2; color: #ef4444; }
    .eq-result.active { background: #ccfbf1; color: #0d9488; }
  </style>
</head>
<body>

  
  <div class="controls">
    <button class="play-btn" id="playBtn" aria-label="Play/Pause">⏸</button>
    <button class="step-btn active" id="btn1" onclick="setStep(1)">1. Start with 4</button>
    <button class="step-btn" id="btn2" onclick="setStep(2)">2. Take 1 away</button>
    <button class="step-btn" id="btn3" onclick="setStep(3)">3. 3 left</button>
  </div>

  
  <div class="stage step-1" id="stage">
    <div class="stage-title" id="stageTitle">4 strawberries in total</div>

    <div class="grid">
      <div class="item-card">
        <span class="emoji">🍓</span>
        <span class="num-badge">1</span>
      </div>
      <div class="item-card">
        <span class="emoji">🍓</span>
        <span class="num-badge">2</span>
      </div>
      <div class="item-card">
        <span class="emoji">🍓</span>
        <span class="num-badge">3</span>
      </div>
      <div class="item-card">
        <span class="removal-tag">−1</span>
        <span class="emoji">🍓</span>
        <span class="num-badge" id="badge4">4</span>
      </div>
    </div>

    
    <div class="equation-bar">
      <span class="eq-part eq-start active" id="eq1">4</span>
      <span class="eq-op">−</span>
      <span class="eq-part eq-minus" id="eq2">1</span>
      <span class="eq-op">=</span>
      <span class="eq-part eq-result" id="eq3">3</span>
    </div>
  </div>

  <script>
    let currentStep = 1;
    let timer = null;
    let isPlaying = true;

    const titles = {
      1: "4 strawberries in total",
      2: "Taking 1 away...",
      3: "3 strawberries are left!"
    };

    function setStep(step) {
      currentStep = step;
      const stage = document.getElementById('stage');
      const title = document.getElementById('stageTitle');
      const eq1 = document.getElementById('eq1');
      const eq2 = document.getElementById('eq2');
      const eq3 = document.getElementById('eq3');
      const badge4 = document.getElementById('badge4');

      // Update stage class
      stage.className = `stage step-${step}`;
      title.textContent = titles[step];

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

      // Update equation styling
      eq1.classList.toggle('active', step === 1);
      eq2.classList.toggle('active', step === 2);
      eq3.classList.toggle('active', step === 3);

      badge4.textContent = (step === 2) ? '✕' : (step === 3 ? '−' : '4');
    }

    function nextStep() {
      const next = currentStep >= 3 ? 1 : currentStep + 1;
      setStep(next);
    }

    function startAutoPlay() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 3200);
      isPlaying = true;
      document.getElementById('playBtn').textContent = '⏸';
    }

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

    document.getElementById('playBtn').addEventListener('click', () => {
      if (isPlaying) {
        pauseAutoPlay();
      } else {
        startAutoPlay();
      }
    });

    // Start auto loop
    startAutoPlay();
  </script>
</body>
</html>

You started with 4 strawberries, took 1 away, and now **3 strawberries are left**.

What happens if we start with 5 toy cars and drive 2 of them away?

First, count all 5 cars in your group: 1, 2, 3, 4, 5. Now, slide 2 cars away.

<!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>Taking Away Objects</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8f9fa;
      color: #1e2945;
      padding: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      height: 100%;
    }

    /* Equation Bar */
    .equation-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-bottom: 8px;
      font-size: 24px;
      font-weight: 700;
    }
    .eq-box {
      padding: 4px 14px;
      border-radius: 12px;
      background: #ffffff;
      border: 2px solid #e2e8f0;
      transition: all 0.3s ease;
      min-width: 44px;
      text-align: center;
    }
    .eq-box.active-start {
      border-color: #3a86ff;
      background: #eef5ff;
      color: #3a86ff;
    }
    .eq-box.active-sub {
      border-color: #f03e3e;
      background: #fff5f5;
      color: #f03e3e;
    }
    .eq-box.active-result {
      border-color: #2b8a3e;
      background: #ebfbee;
      color: #2b8a3e;
      box-shadow: 0 4px 12px rgba(43, 138, 62, 0.15);
    }
    .op {
      color: #94a3b8;
      font-size: 22px;
    }

    /* Scene Container */
    .scene-area {
      width: 100%;
      max-width: 580px;
      flex: 1;
      display: grid;
      grid-template-columns: 1.6fr 1fr;
      gap: 10px;
      min-height: 180px;
      position: relative;
    }

    /* Zones */
    .road-zone, .away-zone {
      border-radius: 16px;
      padding: 10px 8px;
      display: flex;
      flex-direction: column;
      position: relative;
      background: #ffffff;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
      border: 2px solid #e9ecef;
      transition: border-color 0.3s ease;
    }
    .road-zone {
      border-color: #cbd5e1;
      background: linear-gradient(180deg, #f8fafc 0%, #f1f5f9 100%);
    }
    .away-zone {
      border-style: dashed;
      border-color: #fca5a5;
      background: #fffafa;
    }

    .zone-title {
      font-size: 13px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 2px 6px 8px;
      color: #64748b;
    }
    .road-zone .zone-title { color: #3a86ff; }
    .away-zone .zone-title { color: #e03131; }

    .track {
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: space-around;
      gap: 4px;
      position: relative;
    }

    /* Road Lane Markings */
    .road-zone .track::after {
      content: "";
      position: absolute;
      left: 0;
      right: 0;
      height: 2px;
      background: repeating-linear-gradient(90deg, #cbd5e1 0, #cbd5e1 10px, transparent 10px, transparent 18px);
      z-index: 1;
    }

    /* Car Card */
    .car-card {
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      z-index: 2;
      transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.4s ease;
    }
    .car-num {
      font-size: 12px;
      font-weight: 800;
      width: 22px;
      height: 22px;
      border-radius: 50%;
      background: #e2e8f0;
      color: #475569;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 6px;
      transition: all 0.3s ease;
    }
    .car-emoji {
      font-size: 34px;
      line-height: 1;
      filter: drop-shadow(0 4px 6px rgba(0,0,0,0.08));
      transition: transform 0.4s ease;
    }

    /* State Transformations */
    /* Step 1: All 5 active */
    body[data-step="1"] .car-card .car-num {
      background: #3a86ff;
      color: #ffffff;
    }

    /* Step 2 & 3: Cars 4 and 5 moved */
    body[data-step="2"] .car-4,
    body[data-step="2"] .car-5,
    body[data-step="3"] .car-4,
    body[data-step="3"] .car-5 {
      opacity: 0.9;
    }

    body[data-step="2"] .car-4 .car-num,
    body[data-step="2"] .car-5 .car-num,
    body[data-step="3"] .car-4 .car-num,
    body[data-step="3"] .car-5 .car-num {
      background: #f03e3e;
      color: #ffffff;
    }

    /* Step 3: Remaining 3 highlighted */
    body[data-step="3"] .car-1 .car-num,
    body[data-step="3"] .car-2 .car-num,
    body[data-step="3"] .car-3 .car-num {
      background: #2b8a3e;
      color: #ffffff;
      box-shadow: 0 0 0 3px rgba(43, 138, 62, 0.25);
    }
    body[data-step="3"] .car-1 .car-emoji,
    body[data-step="3"] .car-2 .car-emoji,
    body[data-step="3"] .car-3 .car-emoji {
      transform: scale(1.12);
    }

    /* Navigation Controls */
    .controls {
      display: flex;
      gap: 8px;
      width: 100%;
      max-width: 580px;
      margin-top: 10px;
    }
    .btn-step {
      flex: 1;
      padding: 10px 4px;
      font-size: 14px;
      font-weight: 700;
      border-radius: 12px;
      border: 2px solid #e2e8f0;
      background: #ffffff;
      color: #64748b;
      cursor: pointer;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 2px;
      transition: all 0.2s ease;
    }
    .btn-step .sub-text {
      font-size: 11px;
      font-weight: 500;
      opacity: 0.8;
    }
    .btn-step.active {
      background: #3a86ff;
      border-color: #3a86ff;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(58, 134, 255, 0.25);
    }
  </style>
</head>
<body data-step="1">

  
  <div class="equation-bar">
    <div class="eq-box active-start" id="box-start">5</div>
    <span class="op">−</span>
    <div class="eq-box" id="box-sub">2</div>
    <span class="op">=</span>
    <div class="eq-box" id="box-result">?</div>
  </div>

  
  <div class="scene-area">
    
    <div class="road-zone" id="road-zone">
      <div class="zone-title">
        <span>Road</span>
        <span id="road-count">5 Cars</span>
      </div>
      <div class="track" id="road-track">
        <div class="car-card car-1">
          <div class="car-num">1</div>
          <div class="car-emoji">🚗</div>
        </div>
        <div class="car-card car-2">
          <div class="car-num">2</div>
          <div class="car-emoji">🚗</div>
        </div>
        <div class="car-card car-3">
          <div class="car-num">3</div>
          <div class="car-emoji">🚗</div>
        </div>
        <div class="car-card car-4" id="slot-car-4">
          <div class="car-num">4</div>
          <div class="car-emoji">🚗</div>
        </div>
        <div class="car-card car-5" id="slot-car-5">
          <div class="car-num">5</div>
          <div class="car-emoji">🚗</div>
        </div>
      </div>
    </div>

    
    <div class="away-zone" id="away-zone">
      <div class="zone-title">
        <span>Slide Away</span>
        <span id="away-count">0</span>
      </div>
      <div class="track" id="away-track"></div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn-step active" onclick="setStep(1)">
      <span>1. Start</span>
      <span class="sub-text">5 Cars</span>
    </button>
    <button class="btn-step" onclick="setStep(2)">
      <span>2. Take 2</span>
      <span class="sub-text">Slide away</span>
    </button>
    <button class="btn-step" onclick="setStep(3)">
      <span>3. Left</span>
      <span class="sub-text">3 Remain</span>
    </button>
  </div>

  <script>
    const car4 = document.getElementById('slot-car-4');
    const car5 = document.getElementById('slot-car-5');
    const roadTrack = document.getElementById('road-track');
    const awayTrack = document.getElementById('away-track');

    const boxStart = document.getElementById('box-start');
    const boxSub = document.getElementById('box-sub');
    const boxResult = document.getElementById('box-result');
    const roadCount = document.getElementById('road-count');
    const awayCount = document.getElementById('away-count');
    const stepBtns = document.querySelectorAll('.btn-step');

    let currentStep = 1;
    let timer = null;

    function setStep(step) {
      currentStep = step;
      document.body.setAttribute('data-step', step);

      stepBtns.forEach((btn, idx) => {
        btn.classList.toggle('active', idx + 1 === step);
      });

      // Update Equation highlights
      boxStart.className = 'eq-box' + (step === 1 ? ' active-start' : '');
      boxSub.className = 'eq-box' + (step === 2 ? ' active-sub' : '');
      boxResult.className = 'eq-box' + (step === 3 ? ' active-result' : '');

      if (step === 1) {
        roadTrack.appendChild(car4);
        roadTrack.appendChild(car5);
        boxResult.textContent = '?';
        roadCount.textContent = '5 Cars';
        awayCount.textContent = '0';
      } else if (step === 2) {
        awayTrack.appendChild(car4);
        awayTrack.appendChild(car5);
        boxResult.textContent = '?';
        roadCount.textContent = '3 Left';
        awayCount.textContent = '−2';
      } else if (step === 3) {
        awayTrack.appendChild(car4);
        awayTrack.appendChild(car5);
        boxResult.textContent = '3';
        roadCount.textContent = '3 Left ✓';
        awayCount.textContent = '−2';
      }
    }

    // Gentle pedagogical auto-cycling (4s per step)
    function autoPlay() {
      timer = setInterval(() => {
        let next = (currentStep % 3) + 1;
        setStep(next);
      }, 4000);
    }

    // Reset auto timer when user interacts manually
    stepBtns.forEach(btn => {
      btn.addEventListener('click', () => {
        clearInterval(timer);
        autoPlay();
      });
    });

    setStep(1);
    autoPlay();
  </script>
</body>
</html>

Count the cars that stayed on the road: 1, 2, 3. Taking 2 away from 5 leaves **3 cars**.

What if you have 3 bouncy balls and give 2 of them to a friend?

Start with 3 balls. Move 2 balls into your friend's hands.

<!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>Taking Away Objects</title>
<style>
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  }

  body {
    background: #f8f9fa;
    color: #1e2945;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    min-height: 100%;
    padding: 16px 12px;
    user-select: none;
  }

  /* Step Controls */
  .stepper {
    display: flex;
    gap: 8px;
    width: 100%;
    max-width: 420px;
    justify-content: center;
  }

  .step-btn {
    flex: 1;
    padding: 8px 4px;
    font-size: 13px;
    font-weight: 600;
    border: 1px solid #e2e8f0;
    background: #ffffff;
    color: #64748b;
    border-radius: 12px;
    cursor: pointer;
    text-align: center;
    transition: all 0.3s ease;
  }

  .step-btn.active {
    background: #8338ec;
    color: #ffffff;
    border-color: #8338ec;
    box-shadow: 0 4px 10px rgba(131, 56, 236, 0.25);
  }

  /* Main Stage */
  .stage {
    position: relative;
    width: 100%;
    max-width: 440px;
    height: 220px;
    margin: 12px 0;
    display: flex;
    gap: 16px;
  }

  .tray {
    flex: 1;
    background: #ffffff;
    border-radius: 16px;
    border: 2px dashed #cbd5e1;
    padding: 12px 8px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    position: relative;
    transition: border-color 0.3s ease, background-color 0.3s ease;
  }

  .tray-stay {
    border-color: #06d6a0;
    background: rgba(6, 214, 160, 0.04);
  }

  .tray-away {
    border-color: #cbd5e1;
  }

  .tray-title {
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #64748b;
  }

  .tray-stay .tray-title {
    color: #059669;
  }

  .tray-away .tray-title {
    color: #8338ec;
  }

  .tray-count {
    font-size: 20px;
    font-weight: 800;
    color: #1e2945;
  }

  /* Ball Elements inside the shared field */
  .ball-field {
    position: absolute;
    inset: 0;
    pointer-events: none;
  }

  .ball {
    position: absolute;
    width: 52px;
    height: 52px;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 35%, #ffd166 0%, #f77f00 70%, #d62828 100%);
    box-shadow: 0 6px 14px rgba(247, 127, 0, 0.35);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 800;
    color: #ffffff;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
    transition: transform 0.6s cubic-bezier(0.34, 1.4, 0.64, 1), opacity 0.4s ease, filter 0.4s ease;
  }

  /* Ball Positions */
  /* Stage 1: All 3 in Left Tray */
  .step-1 .b1 { top: 96px; left: calc(25% - 26px); }
  .step-1 .b2 { top: 44px; left: calc(25% - 56px); }
  .step-1 .b3 { top: 44px; left: calc(25% + 4px); }

  /* Stage 2 & 3: b1 stays left, b2 & b3 move to right tray */
  .step-2 .b1, .step-3 .b1 {
    top: 72px;
    left: calc(25% - 26px);
  }

  .step-2 .b2, .step-3 .b2 {
    top: 68px;
    left: calc(75% - 56px);
  }

  .step-2 .b3, .step-3 .b3 {
    top: 68px;
    left: calc(75% + 4px);
  }

  /* Step highlighting */
  .step-2 .b2, .step-2 .b3 {
    filter: brightness(1.05);
  }

  .step-3 .b1 {
    box-shadow: 0 0 0 4px #06d6a0, 0 8px 18px rgba(6, 214, 160, 0.4);
    transform: scale(1.08);
  }

  .step-3 .b2, .step-3 .b3 {
    opacity: 0.45;
    filter: grayscale(0.5);
  }

  /* Equation display */
  .equation-box {
    width: 100%;
    max-width: 420px;
    background: #ffffff;
    border-radius: 14px;
    padding: 10px 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  }

  .eq-part {
    font-size: 24px;
    font-weight: 800;
    color: #64748b;
    transition: all 0.3s ease;
  }

  .eq-part.highlight-start { color: #f77f00; }
  .eq-part.highlight-away { color: #8338ec; }
  .eq-part.highlight-left {
    color: #059669;
    background: rgba(6, 214, 160, 0.15);
    padding: 2px 10px;
    border-radius: 8px;
  }

  .eq-ghost {
    opacity: 0.15;
  }

  /* Auto/Pause Bar */
  .controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 6px;
  }

  .play-btn {
    background: #ede9fe;
    border: none;
    color: #8338ec;
    font-size: 12px;
    font-weight: 700;
    padding: 6px 14px;
    border-radius: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 4px;
  }
</style>
</head>
<body>

  
  <div class="stepper">
    <button class="step-btn active" id="btn1" onclick="setStep(1)">1. Start (3)</button>
    <button class="step-btn" id="btn2" onclick="setStep(2)">2. Take 2 Away</button>
    <button class="step-btn" id="btn3" onclick="setStep(3)">3. Count Left (1)</button>
  </div>

  
  <div class="stage step-1" id="stage">
    
    <div class="tray tray-stay">
      <span class="tray-title" id="leftTitle">Start Group</span>
      <span class="tray-count" id="leftCount">3</span>
    </div>

    
    <div class="tray tray-away">
      <span class="tray-title" id="rightTitle">Taken Away</span>
      <span class="tray-count" id="rightCount">0</span>
    </div>

    
    <div class="ball-field">
      <div class="ball b1">1</div>
      <div class="ball b2">2</div>
      <div class="ball b3">3</div>
    </div>
  </div>

  
  <div class="equation-box" id="equation">
    <span class="eq-part highlight-start" id="eqA">3</span>
    <span class="eq-part eq-ghost" id="eqOp">−</span>
    <span class="eq-part eq-ghost" id="eqB">2</span>
    <span class="eq-part eq-ghost" id="eqEq">=</span>
    <span class="eq-part eq-ghost" id="eqC">1</span>
  </div>

  
  <div class="controls">
    <button class="play-btn" id="playBtn" onclick="toggleAuto()">
      <span id="playIcon">⏸</span> Auto-Play
    </button>
  </div>

<script>
  let currentStep = 1;
  let isPlaying = true;
  let autoTimer = null;

  const stage = document.getElementById('stage');
  const btn1 = document.getElementById('btn1');
  const btn2 = document.getElementById('btn2');
  const btn3 = document.getElementById('btn3');
  const leftTitle = document.getElementById('leftTitle');
  const leftCount = document.getElementById('leftCount');
  const rightCount = document.getElementById('rightCount');

  const eqA = document.getElementById('eqA');
  const eqOp = document.getElementById('eqOp');
  const eqB = document.getElementById('eqB');
  const eqEq = document.getElementById('eqEq');
  const eqC = document.getElementById('eqC');
  const playIcon = document.getElementById('playIcon');

  function setStep(step) {
    currentStep = step;
    stage.className = 'stage step-' + step;

    btn1.classList.toggle('active', step === 1);
    btn2.classList.toggle('active', step === 2);
    btn3.classList.toggle('active', step === 3);

    if (step === 1) {
      leftTitle.textContent = 'Start Group';
      leftCount.textContent = '3';
      rightCount.textContent = '0';

      eqA.className = 'eq-part highlight-start';
      eqOp.className = 'eq-part eq-ghost';
      eqB.className = 'eq-part eq-ghost';
      eqEq.className = 'eq-part eq-ghost';
      eqC.className = 'eq-part eq-ghost';
    } else if (step === 2) {
      leftTitle.textContent = 'Staying';
      leftCount.textContent = '1';
      rightCount.textContent = '2';

      eqA.className = 'eq-part';
      eqOp.className = 'eq-part highlight-away';
      eqB.className = 'eq-part highlight-away';
      eqEq.className = 'eq-part eq-ghost';
      eqC.className = 'eq-part eq-ghost';
    } else if (step === 3) {
      leftTitle.textContent = 'Left!';
      leftCount.textContent = '1';
      rightCount.textContent = '2';

      eqA.className = 'eq-part';
      eqOp.className = 'eq-part';
      eqB.className = 'eq-part';
      eqEq.className = 'eq-part';
      eqC.className = 'eq-part highlight-left';
    }
  }

  function nextStep() {
    let next = currentStep + 1;
    if (next > 3) next = 1;
    setStep(next);
  }

  function startAuto() {
    stopAuto();
    isPlaying = true;
    playIcon.textContent = '⏸';
    autoTimer = setInterval(nextStep, 3200);
  }

  function stopAuto() {
    isPlaying = false;
    playIcon.textContent = '▶';
    if (autoTimer) {
      clearInterval(autoTimer);
      autoTimer = null;
    }
  }

  function toggleAuto() {
    if (isPlaying) {
      stopAuto();
    } else {
      nextStep();
      startAuto();
    }
  }

  // Start auto play initially
  startAuto();
</script>
</body>
</html>

Every time you take items away, the group gets smaller. Just count the items that stay to find how many are left!

math

Taking Away Objects from a Group to Find How Many Are Left. Physically remove items from a set and count the remaining items.

Early Level Numeracy: Taking Away and Counting Back (Scotland CfE MNU 0-03a)

Early Years Maths: Alive in 5! & How Many Now? (Take Away Within 5)

Primary 1 / Reception: Take Away Cubes and Pictures - Numbers up to 5

At Early Level (P1 / ages 4–5), instruction must prioritize physical manipulation of concrete materials (counters, toys, ten-frames, natural objects) before formal symbolic notation ($-$ or $=$ signs). Encourage mathematical talk through storytelling, nursery rhymes (e.g., 'Five Little Ducks', 'Five Currant Buns'), and the 'First, Then, Now' framework to ground the abstract concept of subtraction into observable real-world actions.

Taking Away Objects from a Group to Find How Many Are Left

Taking Away from 5

Count What Stays