## Content description

Apply the associative, commutative and distributive laws to aid mental and written computation (ACMNA151)

Source: Australian Curriculum, Assessment and Reporting Authority (ACARA)

The commutative and associative rules apply to addition.

In general if *a* and *b* are numbers

*a* + *b* = *b* + *a* (commutative law for addition)

For example, 7 + 8 = 8 + 7

(*a* + *b*) + *c* = *a* + (*b* + *c*) (associative law for addition)

For example, (7 + 5) + 6 = 7 + (5 + 6)

It is not necessary for students to use the names of the laws or identify when a rule is being employed. Students should be aware of the properties and use them for mental and written computation.

They are also important in algebra.