1/4 of the difference of 6 and a number is 200 Take this algebraic expression in 4 parts: The phrase a number means an arbitrary variable, let's call it x The difference of 6 and a number means we subtract x from 6: 6 - x 1/4 of the difference means we divide 6 - x by 4: (6 - x)/4 Finally, the phrase is means an equation, so we set (6 - x)/4 equal to 200 (6 - x)/4 = 200