The difference of twice a number and 4 is at least -27. The phrase a number means an arbitrary variable, let's call it x. x Twice a number means multiply the number by 2 2x and 4 means we add 4 to our expression: 2x + 4 Is at least means an inequality. In this case, it's greater than or equal to: 2x + 4 >= -27 To solve this inequality, type it in the search engine.