A crayon factory makes 4 colors of crayons. They put 2 of each color crayon in each box. The factory produces enough crayons to fill 5 boxes per hour. How many crayons does the factory produce in 4 hours? Think carefully first, then make a decision:
Each box contains 4 * 2 = 8 crayons. In an hour, they make 8 * 5 = 40 crayons. In 4 hours they make 4 * 40 = 160 crayons. So, the answer is 160.