A percentage is a number that relates a part to the whole. Percentages are viewed as portions of 100. In fact, the word percent literally means “per 100.” Percentages can be expressed in percent form, decimal form, and fraction form.
What does it mean to find the percentage of a number? Suppose in a recent survey, 1,200 people were asked if they would vote for a certain candidate. The results showed that 50 percent said yes, that they would vote for the candidate. You can see in the pie chart below that 50% is the same as one half.
In fraction form you know that 50% is one half because 50% equals 50/100, which simplifies to 1/2. This also means that out of all the 1,200 people surveyed, 600 people said yes, they would vote for the candidate, because half of 1,200 is 600.
There are three methods you can use to find the percentage of a number. Regardless of which method you use, you will arrive at the same answer.
Method 1: The first method is to multiply your percentage number by the number you are finding the percentage of, and then divide by 100.
IN CONTEXT
Suppose in a 2,000 calorie diet, 55% of your calories should come from carbohydrates. How many of your calories should be from carbohydrates? To answer this, you need to find 55% of 2,000.
Using the first method, multiply 55 times 2,000, which equals 110,000. Then, divide by 100, which equals 1,100. Therefore, 1,100 calories of your diet should come from carbohydrates.
Method 2: The second method is to write your percentage as a fraction and then multiply it by the number you are finding the percentage of.
IN CONTEXT
Suppose a basketball player’s free-throw percentage is 65%. In a certain game, she attempted to make 6 free throws. How many successful free throws would you expect her to have made? To answer this, you need to find 65% of 6 free throws.
Using the second method, write 65% as a fraction, which is 65/100, then multiply by 6, or 6/1. Multiplying across numerators equals 390, and multiplying across denominators equals 100. Dividing 390 by 100 equals 3.9, and rounding to the nearest whole number provides a final answer of 4 free throws made during the game.
Method 3: The third method is to write your percentage as a decimal and then multiply it by the number you are finding the percentage of.
IN CONTEXT
Suppose you go to a sale where all jewelry is 30% off. If a necklace costs $50, how much money will you save? You need to find 30% of $50.
Using the third method, write 30% as a decimal. You know that 30% is the same as 30 over 100, and dividing 30 by 100 equals 0.30. Next, multiply 0.30 by 50, which equals 15. Therefore, you will save $15 on the necklace.
Source: This work is adapted from Sophia author Colleen Atakpu.