Year 2 - Maths
Add multiples of 10 to 2-digit numbers.
Adding and subtracting ones and tens to and from 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 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 facts to add multiples of 10 to two-digit numbers.
Key Notes
- When adding multiples of ten to a two-digit number, the tens digit changes but the ones digit stays the same.
- Number facts can be used to help add and subtract multiples of ten to and from a two-digit number.
Vocabulary To Learn
- Multiples of ten: The numbers that are said when we count on in tens from zero. Multiples of ten always have a ones digit of zero.
- Recombine: To add the parts of a number gained through partitioning the whole to reach the whole amount again.
Common Mistakes To Avoid
- Children may automatically count on in tens to add a multiple of ten.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
When adding multiples of ten to a two-digit number, the tens digit changes but the ones digit stays the same. Number facts can be used to help add and subtract multiples of ten to and from a two-digit number.
2. Use this key word in a maths sentence and explain it clearly. 'Multiples of ten'
The numbers that are said when we count on in tens from zero. Multiples of ten always have a ones digit of zero. 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 automatically count on in tens to add a multiple of ten. Correction: Discuss efficiency and compare different methods. Use practical equipment to draw attention to the relationship between adding multiples of ten in two-digit numbers and the known facts they already possess.
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
- 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 bonds to 10 to add/subtract one-digit and two-digit numbers 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.