Year 2 - Maths
Halve even 2-digit numbers and multiples of 10
Multiplying by 2, doubling and halving (factors and products)
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils will learn how multiplication with 2 as a factor relates to doubling and how we can see halving as the inverse of doubling, deriving the related halving fact from a known double.
Lesson Summary
You will learn to halve even 2-digit numbers from 12 to 28 and unitise and apply known facts to halve even multiples of 10.
Key Notes
- Halving facts to 10 can help to halve 2-digit numbers.
- To halve 2-digit numbers, partition the 2-digit number, halve the tens and the ones, then recombine.
Vocabulary To Learn
- Double / Doubling: To become twice as many / to multiply by two.
- Half / Halving: One of two equal parts of a whole. To divide into two equal parts.
- Partition: The act of splitting an object or value down into smaller parts.
Common Mistakes To Avoid
- Incorrectly partitioning and halving odd multiples of 10
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Halving facts to 10 can help to halve 2-digit numbers. To halve 2-digit numbers, partition the 2-digit number, halve the tens and the ones, then recombine.
2. Use this key word in a maths sentence and explain it clearly. 'Double / Doubling'
To become twice as many / to multiply by two. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Incorrectly partitioning and halving odd multiples of 10. Correction: Ensure children use representations where they are able to see the partitioning of the number into an even multiple of 10 and 10 more. That way, they can clearly see they are still finding half of 30 for example.
More Lessons In This Unit
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