Fraction calculator

How it works

Addition and subtraction find the lowest common denominator, rewrite both fractions over it and add the numerators. Multiplication multiplies the two numerators and the two denominators directly. Division flips the second fraction and multiplies. The result is then reduced by dividing top and bottom by their greatest common divisor, which also turns a negative denominator positive by moving the sign to the numerator. An improper result is shown as a mixed number as well, and the decimal is the numerator divided by the denominator. Denominators must be whole numbers other than zero.

Worked example

Take 6/8 + 3/4. Over the common denominator 8 that is 6/8 + 6/8 = 12/8, which divides by 4 to give 3/2 in lowest terms. As a mixed number that is 1 1/2, and 3 divided by 2 is 1.5. A zero denominator is refused instead of producing an error, because dividing by zero has no answer.

Questions and answers