We ordered w pizzas. Each pizza has the same number of slices. If there were a total of x slices How many slices are there in each pizza?
There are w pizzas. 
Each pizza has the same number of slices. 
There are a total of x slices. 

We need to find out how many slices are there in each pizza. 

This can be represented as follows: 

w pizzas 
x slices 
---- 
y slices in each pizza 

We know that there are w pizzas and that there are a total of x slices. 

This means that the number of slices in each pizza is equal to the total number of slices divided by the number of pizzas. 

y = x/w 

y is the number of slices in each pizza.