Year 2 - Maths
Solve problems involving addition and subtraction
Addition and subtraction of two 2-digit numbers
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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 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 solve problems involving the addition and subtraction of two-digit numbers.
Key Notes
- When solving problems, it must be decided whether to add or subtract in order to solve it.
- If the ones digits crosses the tens boundary, it shows that the bridge 10 strategy can be used.
- A number line can be drawn or visualised to help solve problems efficiently.
Vocabulary To Learn
- Addition: Addition involves finding the total, or sum, by combining two or more numbers.
- Subtraction: Subtraction involves taking one number away from another.
- Bridge 10: An addition or subtraction strategy where numbers are partitioned to reach the previous or next multiple of 10, so bonds to 10 can be used to calculate more efficiently.
Common Mistakes To Avoid
- When solving problems involving equations with more than two parts, children may automatically consider the numbers in the order given instead of considering the order they would find easier.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When solving problems, it must be decided whether to add or subtract in order to solve it. If the ones digits crosses the tens boundary, it shows that the bridge 10 strategy can be used.
2. Use this key word in a maths sentence and explain it clearly. 'Addition'
Addition involves finding the total, or sum, by combining two or more numbers. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: When solving problems involving equations with more than two parts, children may automatically consider the numbers in the order given instead of considering the order they would find easier. Correction: Encourage children to solve equations in different orders, comparing which they find easiest and articulating their thinking as they calculate.
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 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 addition strategies to calculate Study Guide
- Use efficient methods to solve subtraction equations Study Guide
Browse all guides in the Year 2 Maths guide library.