New
New
Year 1

# Crossing the tens boundary counting forwards and backwards

I can count forwards and backwards within 100, crossing the tens boundary.

New
New
Year 1

# Crossing the tens boundary counting forwards and backwards

I can count forwards and backwards within 100, crossing the tens boundary.

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## Lesson details

### Key learning points

1. The numbers from 0 to 100 have patterns that can help us to count forwards and backwards across the tens boundary.
2. They are arranged differently on a number track and on a one hundred square.
3. We can count the numbers in two ways.
4. When a number ends in a 9, it is always followed by a decade number when counting in ones.

### Common misconception

Confusion around the numbers which cross the tens boundary, e.g. 39, 40 may say 39, 30

Make errors for the children to discuss; encourage them to explain and correct mistakes.

### Keywords

• Cross the tens boundary - The point at which the counting moves from one decade into another.

• Forwards - When you count forwards the number become greater.

• Backwards - When you count backwards the number become less.

Provide regular daily opportunities to count to one hundred as a class and as a small group or individual basis.
Teacher tip

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Starter quiz

### 6 Questions

Q1.
When does the pattern of counting change when counting backwards?
Correct answer: when you cross the tens boundary
when you count the forties
Q2.
I'm thinking of a number. It is in the fifties and ends in 6. What is my number?
65
506
Q3.
Sort these numbers in the order you would say them if counting forwards.
1 - 5 tens 7
2 - 5 tens 8
3 - 5 tens 9
4 - 6 tens
Q4.
Lucas counts backwards from the number 76. What numbers will he say next?
Correct answer: 75, 74, 73
77, 78, 79
Q5.
When counting forwards from 34, which of these numbers will you say?
29
34
Q6.
When counting backwards from 34, which of these numbers will you say?
35
43

## Exit quiz

### 6 Questions

Q1.
Aisha starts counting at 49 and finishes at 54. She must be counting __________.
backwards
Q2.
When counting backwards from 60, which of these numbers would come first in the count?
37
47
Q3.
Lucas is counting forwards from a number ending in 9. What was the number he started at?
29
49
Q4.
Aisha is counting backwards from a decade number. What was the decade number she started at?
60
50
Q5.
Lucas is counting forwards from 45. What is the next decade number he will say?
40