How do you add 40 percent to a given quantity?

Percentages seem to confuse a lot of people but they really shouldn't. A percentage is simply a fraction. 40% is written as .40 or 4/10. So let's say your given number is 20. To add 40% to 20 you multiply 20 by 1.4 and the answer is 28. The reason you multiply by 1 is you are ADDING 40% so you want the original number you started with. 20 times 1 equals 20. So we have our original number in our answer. The .4 comes from 40%. 20 times .4 equals 8. So 20 plus 8 equal 28.