A pizza shop offers five different toppings, R, P, 0, M, S for its pizzas. How many different pizzas can be created using three different toppings?

What did you get for the answer?

It won't takle long for you to write out all possible combinations for these 5 toppings taken three at a time. By the way, that's a good hint: "combinations of 5 things 3 at a time" - have you learend about combinations and permutations yet?