If 72 is added to a number it will be 4 times as large as it was originally The phrase a number means an arbitrary variable. Let's call it x. x 72 added to a number: x + 72 4 times as large as it was originally means we take the original number x and multiply it by 4: 4x Now, the phrase it will be means an equation, so we set x + 72 equal to 4x to get our final algebraic expression: x + 72 = 4x If the problem asks you to solve for x, we type this equation into our search engine and we get: x = 24