How to add and subtract fractions

Adding and subtracting fractions

Common denominators

It's easy to add and subtract fractions when the numbers on the bottom are the same.

These are called the denominators.

An infographic showing how two ninths plus five ninths equals seven ninths

Equivalent fractions

However, sometimes the denominators are different.

You use equivalent fractions to make them the same.

A common multiple of 2 and 3 is 6.

So, for each fraction we need an equivalent fraction with a denominator of 6.

Now you can add these together.

A three line calculation showing how one half plus one third equals five sixths.
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