An index is sometimes called a power or an exponent.

In 5^{4}, the 4 is the index and the 5 is the base.

5^{4} is read as "5 to the power 4" or "5 to the 4" and means 5 x 5 x 5 x 5.

**Dividing numbers**

When we divide numbers *with the same base number*, we can just

**subtract**the indices.

5^{7} ÷ 5^{3} = 5^{4}

This is because, when we divide we can cancel a 5 on the top with a 5 on the bottom, leaving four 5s on the top.