We ordered 7 pizzas. Each pizza has the same number of slices. If there were a total of 14 slices how many slices are there in each pizza?
Let's denote the number of slices in each pizza by s. Then the number of slices in 7 pizzas is 7s. 

We know that the total number of slices is 14. 

Therefore 

14=7s 

s=2