Year 2 - Maths
Solve equations involving the subtraction of two-digit numbers
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 equations involving the subtraction of two-digit numbers.
Key Notes
- The known part can be partitioned into tens and ones before subtracting to help subtract two-digit numbers.
- Known facts and the partitioning of numbers can be used to help solve missing number equations.
Vocabulary To Learn
- Partition: To split a whole up into parts - a piece or section of a whole.
- Part: A piece or section of a whole.
Common Mistakes To Avoid
- Children may partition both the whole and the parts when subtracting two 2-digit numbers. They need to know to avoid this because it gives an incorrect answer when subtracting numbers which bridge 10
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The known part can be partitioned into tens and ones before subtracting to help subtract two-digit numbers. Known facts and the partitioning of numbers can be used to help solve missing number equations.
2. Use this key word in a maths sentence and explain it clearly. 'Partition'
To split a whole up into parts - a piece or section of a whole. 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 partition both the whole and the parts when subtracting two 2-digit numbers. They need to know to avoid this because it gives an incorrect answer when subtracting numbers which bridge 10. Correction: You may wish to explore further examples which do and do not reach the correct answer, articulating why this is the case and coming to the generalisation that, when subtracting, only one part needs to be partitioned into tens and ones.
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 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 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.