The phrase a number means an arbitrary variable. We can pick any letter a-z except for i and e. Let's choose x. 5 times a number 5x Sixteen subtracted from five times a number 5x - 16 the number plus 4: x + 4 Equals means we set 5x - 16 equals to x + 4 for our algebraic expression: 5x - 16 = x + 4 If you have to solve for x, type this expression into our math solver and we get: x = 5