🎓 Algorithm & Patterns – Year 3 (ACARA Code : AC9M3N07)
🎯Focus:
🧠 Recognise and continue number patterns that double or halve.
➗ Explain that halving is the inverse of doubling and connect this to the 2 times table.thenational+1
✖️ Use a doubling and halving algorithm to make multiplication facts easier, for example turning
Key Ideas (Quick Guide)
- ⭐ Doubling means adding the same again or having two equal groups of a number.
- ⭐ Halving means splitting a number into two equal groups; it is the inverse of doubling
- ⭐ If you know the double fact, you also know the half fact (if double 7 is 14, then half of 14 is 7).
🎥Video Lessons
💡 Video Tips:
- 👀 Pause at each pattern and ask students, “What changed? What stayed the same?”
- ✏️ Suggest different ways to double and halve their way to an easier fact
- ✖️➗ Model problems with arrays, counters or quick sketches so they can see that when one factor is doubled and the other is halved,
- 🗣️ Explain what each operation means
🧩 Mini Quiz – Quick Check
Try these after watching the video:
❓Question 2: Can doubling lead to odd number?
✅ Answer: No, doubling always leads to Even numbers and 2 is always a factor of the doubled number.
❓Question 3: If you double 9, what do you get?
✅ Answer: 18
❓Question 4: Which number is double 15?
✅ Answer: 30
❓Question 5: What is half of 18?
✅ Answer: 9
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📚 Other Lessons in This Unit
🚀 Learning Path (Recommended Order)
| Step | 🔗 Lesson | 💡 What You Learn |
|---|---|---|
| 1️⃣ | 🧠 Doubling and Halving Number Patterns Explained | Easy Math Algorithms for Kids ⭐ You are here⭐ | Learn how numbers grow and shrink using doubling and halving rules |
| 2️⃣ | 📝 Divisibility Rules for 2, 5 and 10 | How to Identify Multiples Fast (Easy Math Tricks for Kids) | Spot number patterns and quickly identify multiples |
| 3️⃣ | 💡Multiply by 3 Trick: Double and Add Method | Easy Mental Math Strategy for Kids | Use a step-by-step rule to multiply by 3 easily |
| 4️⃣ | 🪙How to Count 5c and 10c Coins Fast | Money Math for Kids (Multiples of 5 and 10) | Sort coins and calculate totals using multiplication |
Next Lesson: ➡️ 📝 Divisibility Rules for 2, 5 and 10 | How to Identify Multiples Fast (Easy Math Tricks for Kids)