Year 1 - Maths
Counting forwards and backwards in 10s to 100
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 recite the decade number names from 0-100 in tens, going forwards and backwards, and notice the patterns in the count.
Key Notes
- Decade numbers are used when counting forwards and backwards in tens.
- You can start counting from any decade number.
- When you count forwards, the numbers are greater than the starting number.
- When you count backwards, the numbers are smaller than the starting number.
Vocabulary To Learn
- Number names 60 - 100: e.g. "sixty" corresponding to 60
Common Mistakes To Avoid
- Confusion between teen and decade numbers, e.g. 19 and 90, leading to errors in counting 80, 90, 20
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
Decade numbers are used when counting forwards and backwards in tens. You can start counting from any decade number.
2. Use this key word in a maths sentence and explain it clearly. 'Number names 60 - 100'
e.g. "sixty" corresponding to 60. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Confusion between teen and decade numbers, e.g. 19 and 90, leading to errors in counting 80, 90, 20. Correction: Regular identification and discussion of common errors with opportunities to correct them within this lesson can be replicated beyond it.
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