Year 1 - Maths
Counting forwards and backwards in 10s to 50
Counting in tens - decade numbers
Study Hub
Study Guides
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 0-50, 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 in tens from any decade number.
- A 100 square can be used to help you count the decade numbers.
Vocabulary To Learn
- Number names 10 to 50: E.g. 'ten' for 10
- Decade numbers: These are the multiples of ten which mark the tens boundary where the pattern of counting changes.
Common Mistakes To Avoid
- May confuse decade number names with teen numbers e.g. thirteen, thirty.
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 in tens from any decade number.
2. Use this key word in a maths sentence and explain it clearly. 'Number names 10 to 50'
E.g. 'ten' for 10. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: May confuse decade number names with teen numbers e.g. thirteen, thirty. Correction: Regular identification and discussion of common errors with opportunities to correct them within this lesson can be replicated beyond it.
More Lessons In This Unit
Browse all guides in the Year 1 Maths guide library.