# Count a large group of objects by counting tens and ones

I can count larger groups of objects efficiently using tens and ones to help me.

# Count a large group of objects by counting tens and ones

I can count larger groups of objects efficiently using tens and ones to help me.

## Lesson details

### Key learning points

- One item can be used to represent several other items. This is called unitising.
- The order in which tens and ones are arranged does not affect the value of the number.
- We can use a one hundred square to help find the value of two-digit numbers more efficiently.

### Common misconception

Children may continue counting in tens when they reach the ones, e.g. count 2 tens and 3 ones completely in tens. They may think arrangement of tens and ones affects how to count them.

Make deliberate errors to prompt discussion and refer back to previous stem sentences, e.g. 'The objects are in ones, so I can count them in ones.' Present tens and ones in non-standard arrangements, so children practise always counting tens first.

### Keywords

Unitising - Unitising means treating groups that contain, or represent, the same number of things as ‘ones’ or ‘units’. It is important in understanding place value and supports us to think multiplicatively.

### 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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## Starter quiz

### 6 Questions

7 groups of ten and 3 more ones

9 groups of ten and 4 more ones

3 groups of ten and 7 more ones

4 groups of ten and 9 more ones