A restaurant offers pizzas with 3 types of crust, 7 different toppings, and in 6 different sizes. How many different one-topping pizzas could be ordered?
There are 7 toppings to choose from, so there are 7 one-topping pizzas that could be ordered for each of the 6 different sizes. Therefore, there are 7 * 6 = 42 different one-topping pizzas that could be ordered. Answer: \boxed{42}.
