Year 2 - Maths
Use efficient addition strategies to calculate
Addition and subtraction of two 2-digit numbers
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Study Guides
This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
In this unit pupils apply their knowledge of known facts and understanding of place value to add and subtract with 2-digit numbers both within and across the tens boundary.
Lesson Summary
You will learn to identify addition strategies to calculate efficiently.
Key Notes
- We can use strategies we already know to help us prepare for the addition of two 2-digit numbers.
- It is important to be able to calculate mentally before adding two 2-digit numbers.
Vocabulary To Learn
- Calculate: To work out an answer, often by adding or subtracting.
- Efficiently: Not wasting time or effort. An efficient strategy is one we can carry out easily.
Common Mistakes To Avoid
- Children may not be able to mentally calculate or identify efficient strategies and so revert to counting on in ones.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
We can use strategies we already know to help us prepare for the addition of two 2-digit numbers. It is important to be able to calculate mentally before adding two 2-digit numbers.
2. Use this key word in a maths sentence and explain it clearly. 'Calculate'
To work out an answer, often by adding or subtracting. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Children may not be able to mentally calculate or identify efficient strategies and so revert to counting on in ones. Correction: Assess use of mental strategies before starting this lesson as it is important to be fluent in using strategies with smaller numbers before working with larger numbers to avoid reverting to inefficient counting strategies.
More Lessons In This Unit
- Add 2-digit numbers when crossing the tens boundary Study Guide
- Add two-digit numbers without crossing the tens boundary Study Guide
- Combine tens and ones within equations Study Guide
- Create addition and subtraction problems Study Guide
- Explain different strategies used to subtract Study Guide
- Find the missing addend when adding two-digit numbers Study Guide
- Find the missing part when subtracting two-digit numbers Study Guide
- Solve equations involving the subtraction of two-digit numbers Study Guide
- Solve problems involving addition and subtraction Study Guide
- Solve problems involving subtraction of two-digit numbers Study Guide
- Solve problems involving subtraction when bridging 10 Study Guide
- Solve problems involving the addition of two-digit numbers Study Guide
- Subtract two-digit numbers crossing the tens boundary Study Guide
- Use efficient methods to solve subtraction equations Study Guide
Browse all guides in the Year 2 Maths guide library.