The difference between two nearest values is 70 (210 and 280). So round off the numbers to the nearest integers. 30.21% of 260 - 30% of 260; 59.84% of 510~ 60% of 510 and 103.57-104 Now the equation will become 30% of 260 + 60% of 510 -104 = ? 30/100 x 260 + 60/100 x 510 -104=? 78 + 306-104 = ? ?=384-104=280