How to Multiply Fractions by Percentages

By Charlotte Johnson
One slice of pie represents a fraction of the entire pie.
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Fractions and percentages are related mathematical concepts because they both deal with the relationship of a part to a whole. You will encounter fractions and percentages in math courses from middle school through college. You also may run into fractions and percentages in everyday life, such as when you are shopping or constructing a budget. You can multiply fractions and percentages if you convert them to the same format first. This requires a few simple calculations.

Write down the fraction and the percentage that you want to multiply. You might want to multiply 4/5 and 75 percent, for instance.

Convert the percentage to a fraction by placing the number over 100. In this example, you would place 75 over 100 so that your multiplication sentence would look like this: 4/5 * 75/100.

Multiply the numerators (top numbers) b each other and the denominators (bottom numbers) times each other. In this example, you would multiply 4 by 75 to get 300 and 5 by 100 to get 500. Therefore, your initial answer would be 300/500.

Simplify the fraction if possible by dividing the numerator and denominator by the greatest common factor. In this case, you would divide 300 and 500 by 100, since 100 is the largest number that will evenly fit into both values. Your simplified answer would be 3/5.