by approximately what percent is x greater than 4 / 5 if ( 4 / 5 ) ( x ) = 1 ?
4 / 5 = 80 % , 5 / 4 = 125 % increase by 45 percentage points 45 / 80 = 56 % , hence b
multiply(divide(subtract(5, divide(4, 5)), divide(4, 5)), const_100)