There are three rules to remember - known as the Laws of Indices.

They only apply when working with the same base numbers.

The laws deal with raising base numbers to powers.

For example:

`2^3 xx 2^4`

`= (2xx2xx2) xx (2xx2xx2xx2) = 2^7`

which is the same as adding the indices.

The law for multiplying is `2^m xx 2^n = 2^((m+n))`

There is a similar law for dividing:

`4^5 ÷ 4^3`

`= frac(4xx4xx4xx4xx4)(4xx4xx4)`

`= 4 xx4 = 4^2`

and in this case the same answer is obtained by subtracting the indices.

The law for dividing: `4^m÷4^n=4^((m-n))`

When raising a number to a further power, the indices are multiplied:

`(5^3)^2` (5 raised to the power of three, then raised to the power of 2)

`(5 xx5 xx 5) xx (5 xx 5 xx 5) = 5^6`

and can be re-written by multiplying the indices.

The law for raised to a power: `(5^m)^n = 5^((mxxn))`.