Year 1 - Maths
Explain that the digits in the numbers 11 to 19 express quantity
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 explain that the digits in the numbers 11 to 19 express quantity.
Key Notes
- The digits in the numbers 11-19 tell us about their value.
- The teen numbers are between 10 and 20
- The teen numbers can be represented as ten and a bit.
- We can say there is one ten and --- ones.
Vocabulary To Learn
- Teen numbers: A number made of a ten (a group of 10 ones) and some additional ones.
- Tens: A ten is a group of 10 ones.
- Ones: Individual objects, grouped in ones.
Common Mistakes To Avoid
- Pupils confuse e.g. 18 and 80 because they sound similar.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
The digits in the numbers 11-19 tell us about their value. The teen numbers are between 10 and 20.
2. Use this key word in a maths sentence and explain it clearly. 'Teen numbers'
A number made of a ten (a group of 10 ones) and some additional ones. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils confuse e.g. 18 and 80 because they sound similar. Correction: Take time to emphasise the pronunciation of the teen numbers and provide lots of opportunities for pupils to say and repeat the words. You may wish to practise the teen and decade numbers side by side so pupils can hear the difference.
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
- 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 10 and a bit to solve problems 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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