Index notation – WJECZero and negative indices

Indices are a way of representing numbers and letters that have been multiplied by themselves a number of times. They help us to complete problems involving powers more easily.

Part ofMathsNumber

Zero and negative indices

Power of 0

Example

p2 ÷ p2

We need to look at this in two ways.

Using the rule for dividing indices:

p2 ÷ p2 = p2-2

= p0

But we know that anything divided by itself is 1.

So p0 = 1.

Anything to the power of 0 is equal to 1.

Negative indices

Example

32 ÷ 34

Using the rule for dividing indices:

32 ÷ 34 = 3-2

But we also know that:

A worked example of how to divide indices by subtracting the powers.

So 3-2 = \(\frac{1}{3^2}\)

which is equal to \(\frac{1}{9}\) when evaluated.

For negative indices, a-m = \(\frac{1}{a^m}\)

Question

What is the value of 2-3 ?