What is a fraction?

This pizza has been cut into three equal parts. We call these thirds. A third is written as

The whole pizza cut into three equal parts gives us three thirds. Think about just one slice. We can write this using a fraction .

Think about two slices. Two slices is two thirds. We can write two thirds as

The top number of the fraction tells us how many slices we have.
We call it the numerator.


The bottom number tells us how many parts in the whole pizza.
We call it the denominator.