Fractions are comprised of a numerator and a denominator. The denominator represents the number of parts that make up one whole, and the numerator represents the number of those parts in the fraction. For example, 3/5 would mean that five parts equals one whole, and this fraction has three parts. If you wanted to find a percentage of a fraction, you need to know how to convert a percentage to a decimal and how to multiply that decimal by the fraction.
Divide the percent by 100 to convert it to a decimal. For example, if you want to find 20 percent of 5/7, first divide 20 by 100 to get 0.2.
Multiply the decimal by the numerator of the fraction. In this example, multiply 0.2 by 5 to get 1.
Place the result from the previous step over the original denominator. In this example, you would place 1 over 7 to find that 1/7 equals 20 percent of 5/7. If you want to convert to a decimal, simply divide the numerator by the denominator. In this example, 5/7 equals 0.7143.