The numerator is the top number in a fraction. The denominator is the bottom number in a fraction. Ex 3/5. 3 is the numerator, 5 is the denominator. Here is some extra info :). Divide the numerator by the denominator to get the decimal form of the fraction, Ex, 5/10 Turn into 5÷10=.5. .5 is the decimal form of 5/10.