Year 1 - Maths
Use knowledge of 10 and a bit to solve problems
Composition of numbers 11 to 19
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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 explain 11-19 as cardinal and ordinal numbers. They will double and halve numbers 6-9 and use addition and subtraction facts to add and subtract within 20.
Lesson Summary
You will learn to use your knowledge of 10 and a bit to solve problems.
Key Notes
- The teens numbers can be partitioned into ten and a bit.
- Problems can be represented using part-part-whole models, tens frames and sum equations.
- The 10 and a bit can be represented in the problem.
Vocabulary To Learn
- Partition: The act of splitting an object or value down into smaller parts.
- Part: A piece or section of the whole.
- Sum: The total when numbers are added together.
Common Mistakes To Avoid
- Pupils continue to count all when finding the sum instead of counting on from 10 or using their developing fluency with partitioning teen numbers into 10 and a bit.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The teens numbers can be partitioned into ten and a bit. Problems can be represented using part-part-whole models, tens frames and sum equations.
2. Use this key word in a maths sentence and explain it clearly. 'Partition'
The act of splitting an object or value down into smaller parts. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils continue to count all when finding the sum instead of counting on from 10 or using their developing fluency with partitioning teen numbers into 10 and a bit. Correction: Provide concrete and pictorial examples where 10 is provided as a group that is hard to separate and count. Continue to emphasise one ten as a group of 10 that does not need to be counted in ones.
More Lessons In This Unit
- Double the numbers 6 to 9 and halve the result explaining what doubling and halving is Study Guide
- Explain that the digits in the numbers 11 to 19 express position on a number line Study Guide
- Explain that the digits in the numbers 11 to 19 express quantity Study Guide
- Explore odd and even numbers within 20 Study Guide
- Identify the quantity shown in a representation of numbers 11 to 19 Study Guide
- Solve subtraction problems using knowledge of 10 and a bit Study Guide
- Use knowledge of addition and subtraction facts within 10 to add and subtract within 20 Study Guide
- Use knowledge of addition facts within 10 to add within 20 Study Guide
- Use knowledge of subtraction facts within 10 to subtract within 20 Study Guide
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