2 times a number equals that number plus 5 The phrase a number means an arbitrary variable, let's call it x. 2 times a number means we multiply 2 by x: 2x That number plus 5 means we add 5 to the number x x + 5 The phrase equals means we set both expressions equal to each other 2x = x + 5 <-- This is our algebraic expression If you want to take this further and solve this equation for x, type this expression in the search engine and we get: x = 5