Year 3 - Maths
Use known facts to add and subtract to and from multiples of 100
Representing 3-digit numbers, comparing and positioning on number lines
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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 use knowledge of place value to represent a 3-digit number in different ways. They will compare and order 3-digit numbers and position on number lines and unmarked number lines.
Lesson Summary
You will learn to add to and subtract from multiples of 100.
Key Notes
- When you add a one-digit number and a multiple of 100, only the 1s digit changes.
- When you subtract a one-digit number from a multiple of 100, the 100s, 10s and 1s digits change.
- When you add a 10s number and a multiple of 100, only the 10s digit changes.
- When you subtract a 10s number from a multiple of 100, the 100s and 10s digits change.
Vocabulary To Learn
- multiple: A multiple is the result of multiplying a number by another whole number.
Common Mistakes To Avoid
- Pupils may need help using number pairs that total 10 to support their thinking in this lesson.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When you add a one-digit number and a multiple of 100, only the 1s digit changes. When you subtract a one-digit number from a multiple of 100, the 100s, 10s and 1s digits change.
2. Use this key word in a maths sentence and explain it clearly. 'multiple'
A multiple is the result of multiplying a number by another whole number. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may need help using number pairs that total 10 to support their thinking in this lesson. Correction: Make explicit connections between number pairs that total ten and the learning (e.g. 10 - 3 = 7 so 100 - 7 = 93 and 100 - 30 = 70).
More Lessons In This Unit
- Add and subtract to and from a 3-digit number bridging 100 Study Guide
- Comparing and ordering numbers with 1, 2 and 3 digits Study Guide
- Count forwards and backwards in multiples of 2, 20, 5, 50 and 25 Study Guide
- Count forwards and backwards within 3-digits Study Guide
- Estimate the position of 3-digit numbers on unmarked number lines Study Guide
- Ordering sets of 3-digit numbers Study Guide
- Partition 3-digit numbers in different ways Study Guide
- Position 3-digit numbers on number lines Study Guide
- Represent a 3-digit number up to 1,000 in different ways Study Guide
- Solve problems by adding and subtracting to or from 3-digit numbers Study Guide
- Solve problems by counting forwards and backwards in multiples of 2, 20, 5, 50 and 25 Study Guide
- Use known facts to add and subtract multiples of 100 within 1000 Study Guide
- Use known facts to solve problems involving partitioning numbers Study Guide
- Write a 3-digit multiple of 10 as a multiplication equation Study Guide
Browse all guides in the Year 3 Maths guide library.