# Use properties of numbers and the commutative and associative laws to simplify calculations

I can use properties of numbers and the commutative and associative laws to simplify calculations.

# Use properties of numbers and the commutative and associative laws to simplify calculations

I can use properties of numbers and the commutative and associative laws to simplify calculations.

## Slide deck

## Lesson details

### Key learning points

- By rearranging a calculation it can be made easier to solve mentally

### Common misconception

Pupils may struggle to find factors of a number if they do not have automatic recall of their times tables.

Provide children with a multiplication grid to help pupils understand the process of the calculations, however ensure additional support is in place for children to build towards automatic recall of times tables.

### Keywords

Factor - Factors are whole numbers which exactly divide another whole number.

Commutative - The commutative law states that you can write the values of a calculation in a different order without changing the calculation; the result is the same. It applies for addition and multiplication.

Associative - The associative law states that it doesn't matter how you group or pair values (i.e. which we calculate first), the result is still the same. It applies for addition and multiplication.

### 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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## Worksheet

## Starter quiz

### 6 Questions

4 and 9

2 and 14

5 and 13

## Exit quiz

### 6 Questions

16 × 15

18 × 24

21 × 12

33 × 20