Math Basics


What are the rules for multiplying and dividing fractions?

As to be expected, there are rules for multiplying and dividing fractions. Multiplication of factions is very straight forward—just multiply the numerators and denominators, then simplify the resulting fraction, if needed (or if you can). For example, 2/5 × 4/7 = (2 × 4) / (5 × 7) = 8/35 (this number cannot be simplified).

Division of fractions entails one main rule: You need to flip over, or invert, the “divisor” fraction (the fraction on the bottom) to get the result (this is also called the reciprocal of the fraction; see below). Here are the steps: First change the division sign to a multiplication sign after inverting the fraction to the right of the sign. Multiply the numerators and denominators and write the result. You can then simplify or reduce the fraction if needed. For example, ½ ÷ 1/4 = ½ × 4/1 = 4/2. This number can be simplified to 2.


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