When working with fractions you must know what a numerator and denominator is.

### Numerator

A numerator is a number that is used to represent part of a whole. The number can be found above the line or on top in a fraction which shows how many parts are indicated by the denominator are taken. For example: 3 in 3/6 as shown in the diagram above. Here you can find the full definition

Numerator

### Denominator

The denominator is the figure below the numerator in a fraction. Very simply the number at the bottom in any fraction.

Denominator

Adding fractions is a very easy task if you have some background in maths or know a little about maths.

When adding like fractions such as the one below, fractions which have the same denominator you simply add the top numerators and then write the fractions with the numerators addition over the denominator of the two fractions.

## Example

Work out

As simple as that…

## However…

Fractions which have different denominators have to be treated differently. We first have to find the lowest common multiple of the denominators of the fraction in the equation.

## For example

The denominators for this example are different. In this example we have to convert the all the fractions in the equation so that they have the same denominators. The numerators will be affected as well since the denominators are changing.

The LCM of 2 and 3 is a six, so the expression becomes.

Notice that the numerators have been affected as well. For each fraction you had to multiply the denominator by a number to get the LCM. So for;

You had to multiply the denominator 2 by 3 to get a 6. Since you multiplied the bottom you had to do the same to the top. The same for;

Notice we multiplied both the bottom and the top by the same number.

## Another example

Work out

It’s that simple to add fractions…