Using an index or power

An index, or a power, is the small floating number that goes next to a number or letter. The plural of index is indices.

Indices show how many times a number or letter has been multiplied by itself.

Here is a number written in index form:

Example of how to write numbers in index form. Base number shown as 2 and the power or index number shown as 4.

2 is the base number and 4 is the index or power.

24 is a short way of writing 2 \times 2 \times 2 \times 2.

a^2 (read as ' a squared’) is a short way of writing a \times a. a has been multiplied by itself.

Example of how to write letters in algebraic form. Base letter shown as A and the power or index number shown as 3.

a^3 (read as ‘ a cubed’) is a short way of writing a \times a \times a. a has been multiplied by itself three times.

a^4 (read as ‘ a to the power of 4') is a short way of writing a \times a \times a \times a. a has been multiplied by itself four times, and so on.

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a^1 (read as ' a to the power of 1') is written as simply a.