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).

Video

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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
Correct answer: 56
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
Correct answer: 43
34
Q6.
When counting backwards from 34, which of these numbers will you say?
Correct answer: 29
35
43

6 Questions

Q1.
Aisha starts counting at 49 and finishes at 54. She must be counting __________.
Correct answer: forwards
backwards
Q2.
When counting backwards from 60, which of these numbers would come first in the count?
37
47
Correct answer: 57
Q3.
Lucas is counting forwards from a number ending in 9. What was the number he started at?
An image in a quiz
29
49
Correct answer: 39
Q4.
Aisha is counting backwards from a decade number. What was the decade number she started at?
An image in a quiz
60
50
Correct answer: 70
Q5.
Lucas is counting forwards from 45. What is the next decade number he will say?
40
Correct answer: 50
60
Q6.
Aisha is counting backwards from 45. What is the next decade number she will say?
Correct answer: 40
50
30

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