Year 3 - Maths
Use known facts to find complements to 100 efficiently
Securing place value to 100 and applying to addition and subtraction
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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 known facts to find multiples of ten that compose 100 and use known facts to find complements to 100. They will add and subtract multiples of ten, bridging 100.
Lesson Summary
You will learn to use known facts to find complements to 100 efficiently.
Key Notes
- Number facts to 10 can be applied to multiples of 10
- Using pairs to 10 and pairs to 100 we can find pairs to 100
- If we have a pair to 10 then the tens have to total 90 for the whole to be 100
- A number line can represent the complements to 100
Vocabulary To Learn
- Complement to 100: Pairs of numbers which total 100
- Total: The result of adding.
Common Mistakes To Avoid
- Pupils may be less efficient if they are not fluent with bonds within 10 e.g. 3 + 6 = 9
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Number facts to 10 can be applied to multiples of 10. Using pairs to 10 and pairs to 100 we can find pairs to 100.
2. Use this key word in a maths sentence and explain it clearly. 'Complement to 100'
Pairs of numbers which total 100. 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 be less efficient if they are not fluent with bonds within 10 e.g. 3 + 6 = 9. Correction: Provide additional scaffolding as appropriate including examples of pairs that total 9 and 10.
More Lessons In This Unit
- Bridge 100 by adding in multiples of 10 Study Guide
- Bridge 100 by subtracting in multiples of 10 Study Guide
- Composition of 100 in 10s and 1s Study Guide
- Composition of 100 in 50s, 25s and 20s Study Guide
- Multiples of 10 that total 100 Study Guide
- Represent 3-digit multiples of 10 in different ways Study Guide
- Solve problems using knowledge of addition and subtraction of multiples of 10 Study Guide
- Use known facts to find pairs of numbers that total 100 Study Guide
- Use place value knowledge to write addition and subtraction equations Study Guide
Browse all guides in the Year 3 Maths guide library.