New
New
Year 1

# Count groups of 10 in decade numbers

I can recognise when to count in tens and use my decade numbers to find out how many there are altogether.

New
New
Year 1

# Count groups of 10 in decade numbers

I can recognise when to count in tens and use my decade numbers to find out how many there are altogether.

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## Slide deck

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## Lesson details

### Key learning points

1. You can count groups of 10 in two ways.
2. You can count groups of 10 using decade numbers.
3. You can look at the digit before zero to find out how many tens are in a decade number.

### Common misconception

When objects are in 10s, children may count the number of tens rather than the amount altogether.

Introduce errors involving confusion between the number of tens and the amount altogether for children to reason about.

### Keywords

• 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.

Ensure that familiar objects around the room are grouped/stored in tens so children can count as part of daily activities.
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).

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## Worksheet

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## Starter quiz

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### 6 Questions

Q1.
This is not 1 group of 10 because __________
it has 10 objects.
Correct answer: it does not have 10 objects.
Q2.
Which picture is representing 1 ten?
Focusing on the 9 fingers pointing up.
Correct Answer: An image in a quiz
Q3.
How many tens can you see?
10
Correct answer: 1
0
Q4.
Match the groups of 10s to the number of tens they represent.
Correct Answer:4 tens,4 groups of 10

4 groups of 10

Correct Answer:3 tens,3 groups of 10

3 groups of 10

Correct Answer:10 tens,10 groups of 10

10 groups of 10

Correct Answer:7 tens,7 groups of 10

7 groups of 10

Q5.
Which image shows 4 tens?
Correct Answer: An image in a quiz
Q6.
How many tens can you see?
3
2
Correct answer: 1

## Exit quiz

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### 6 Questions

Q1.
This number ends in 0. This tells me that it is a number.
Correct Answer: decade
Q2.
How many tens are in this picture?
Correct answer: 8
80
Q3.
How many pizza slices are there altogether?
8
Correct answer: 70
80
Q4.
Which picture shows 40?
Correct Answer: An image in a quiz
Q5.
Look at the number 90. What does the 9 represent?
9
Correct answer: 9 tens.
It is a decade number.
Q6.
Match the numbers that represent the same amount.
Correct Answer:70,7 tens

7 tens

Correct Answer:50,5 tens

5 tens

Correct Answer:30,3 tens

3 tens

Correct Answer:10,1 ten

1 ten

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