The word "percent" means of each 100. The 100 refers to the whole of the number being considered. Figuring percentages can seem daunting. It requires multiplication and division, and often needs to be done in your head at the spur of the moment. You might need to figure out percentage for a tip at a restaurant or to decide if you want to buy an item that is on sale. Knowing some tricks for figuring percentage quickly is a good way to put your mind at ease.
Some percentages are easier than others. To figure out 50 percent, simply half the whole number. Fifty percent of 40 is 20, for instance. To figure 25 percent quickly, find 50 percent of the whole, and then half that number. Twenty-five percent is half of 50 percent. So, 25 percent of 40 is half of 20, or 10. Seventy-five percent is 50 percent plus 25 percent more. So, 75 percent of 40 is 20 plus 10, or 30.
To find 10 percent, move the decimal point of the number to the left once. This is the same as dividing by 10. Ten percent of 40 is four. Use this number to find out any percentage to the tenth. Thirty percent of 40 is three times four, or 12. To find 1 percent, move the decimal point twice to the left, which is the same as dividing by 100. One percent of 40 is .4, so 3 percent of 40 is 1.2. In this way, you can figure any percentage. Simply find the tens, and then the ones. Thirty-three percent of 40 is 30 percent plus 3 percent, or 13.2.
The most common tip is 15 percent. This is what most people leave the wait staff at a restaurant, for instance. There are two easy ways to figure 15 percent. The first is to half the total bill and then add that amount to the full amount, so that you have a total that is 150 percent. If your bill is 20 dollars, you would add 10, coming up with 30. Next move the decimal point to the right once, to find 10 percent of 150 percent, which is the same as 15 percent. In this case, three dollars. Another easy way to figure 15 percent is to find 10 percent, in this case two dollars, and then add half as much, or 5 percent, in this case one more dollar for a total of three dollars.