Year 2 - Maths
Use number bonds to 10 to add/subtract one-digit and two-digit numbers
Adding and subtracting ones and tens to and from 2-digit numbers
Study Hub
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 will add and subtract 1s and 10s from 2 digit numbers. They will use number facts to add/subtract a single-digit number to/from a 2-digit number. They will use a part-part-whole model to represent addition and subtraction.
Lesson Summary
You will learn to use number bonds to add and subtract one-digit and two-digit numbers.
Key Notes
- When the ones digits in an equation sum to ten, the sum in the equation will always be a multiple of ten.
- When subtracting a one-digit number from a multiple of ten, number bonds to ten can be used.
- The number being subtracted and the ones digit in the answer will be a number bond to ten.
Vocabulary To Learn
- Sum: The result of adding two or more numbers
- Difference: The result of subtracting one number from another. How much one number differs from another.
Common Mistakes To Avoid
- When subtracting, children may use their number bonds to ten to find the correct ones digit, but may forget to consider the previous multiple of ten, e.g. say 40-2=48
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When the ones digits in an equation sum to ten, the sum in the equation will always be a multiple of ten. When subtracting a one-digit number from a multiple of ten, number bonds to ten can be used.
2. Use this key word in a maths sentence and explain it clearly. 'Sum'
The result of adding 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 subtracting, children may use their number bonds to ten to find the correct ones digit, but may forget to consider the previous multiple of ten, e.g. say 40-2=48. Correction: Encourage children to use their knowledge of decades to estimate (e.g. I know 40-2 will be in the thirties), then prove it using representations that highlight the tens structure, e.g. one hundred squares, ten frames and number lines.
More Lessons In This Unit
- Add and subtract 1 to and from a 2-digit number crossing the tens boundary Study Guide
- Add and subtract 10 to and from a 2-digit number. Study Guide
- Add and subtract one to or from a two-digit number within a decade Study Guide
- Add by bridging a multiple of ten Study Guide
- Add multiples of 10 to 2-digit numbers. Study Guide
- Find 10 more or less than a 2-digit number. Study Guide
- Partition 2-digit numbers in different ways Study Guide
- Subtract by bridging a multiple of ten Study Guide
- Subtract multiples of ten from 2-digit numbers Study Guide
- Use bridging to solve addition and subtraction problems Study Guide
- Use efficient strategies to solve problems Study Guide
- Use number facts to add or subtract a one-digit number and a two-digit number. Study Guide
- Use number facts to solve addition and subtraction problems. Study Guide
- Use number facts to solve problems in measures and data contexts Study Guide
Browse all guides in the Year 2 Maths guide library.