Year 1 - Maths
Count groups of 10 in decade numbers
Counting in tens - decade 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 extend their counting to counting the decade numbers which will later be known as multiples of ten and making representations of them using a variety of different manipulatives.
Lesson Summary
You will learn to recognise when to count in tens and use your decade numbers to find out how many there are altogether.
Key Notes
- You can count groups of 10 in two ways.
- You can count groups of 10 using decade numbers.
- You can look at the digit before zero to find out how many tens are in a decade number.
Vocabulary To Learn
- Group: Objects that are gathered together in a set can be said to be in a group.
- Decade numbers: These are the multiples of ten which mark the tens boundary where the pattern of counting changes.
- Represent: The word represent tells you what something is worth or what it means or tells you.
Common Mistakes To Avoid
- When objects are in 10s, children may count the number of tens rather than the amount altogether.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
You can count groups of 10 in two ways. You can count groups of 10 using decade numbers.
2. Use this key word in a maths sentence and explain it clearly. 'Group'
Objects that are gathered together in a set can be said to be in a group. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: When objects are in 10s, children may count the number of tens rather than the amount altogether. Correction: Introduce errors involving confusion between the number of tens and the amount altogether for children to reason about.
More Lessons In This Unit
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