3.5.2 Multiplying fractions
The expression ‘three times two’ just means there are three lots of two (i.e. 2 + 2 + 2). So multiplying by a whole number is just a form of repeated addition. For example,
This is equally true if you are multiplying a fraction by a whole number:
We could write the 3 in the form of its equivalent fraction and it is then clear that the same answer is obtained by multiplying the two numerators together and the two denominators together:
In fact, this procedure holds good for any two fractions.
To multiply two or more fractions, multiply numerators (top lines) together and also multiply the denominators (bottom lines) together.
So
Sometimes cancelling is possible:
