Students learn to solve "number" word problems, such as the following. One number is four times as large as another. The sum of the numbers is 45. Find the numbers. Since the first sentence states that one number is 4 times as large as another, the numbers can be represented as x and 4x. Since the second sentence states that the sum of the numbers is 45, the equation can be set up as x + 4x = 45.