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Maths I

Basic fractions

# Multiplying and dividing fractions

## Multiplying fractions

To multiply fractions, you need to multiply the top numbers (numenators) together, and multiply the bottom numbers (denominators) together.

Remember that you cannot cancel numbers that are both on the top of a fraction.

Have a look at the example below.

Multiply then cancel:

OR cancel between the top and the bottom then multiply:

Question

Calculate:

(The 5s do not cancel each other out because they are both on the top of the fraction).

## Dividing a fraction by a whole number

divided by 3 should be of the original fraction, which would make the answer .

So

=     (writing 3 as )

= .

## Dividing by a fraction

The rule to remember when dividing fractions is that you turn the fraction you are dividing by upside down, and multiply.

So going back to the previous example we can work this out by turning the upside down.

=

Dividing by is the same as multiplying by .

It works with all fractions. For example dividing by is the same as multiplying by .

Question

Calculate:

=

=

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