How it works
Enter fractions as a/b, mixed numbers as whole a/b (with a space, like 1 1/2), whole numbers, or decimals. The answer is reduced to lowest terms and also shown as a mixed number and a decimal.
To add or subtract, the fractions are put over a common denominator. To multiply, numerators and denominators are multiplied straight across. To divide, the second fraction is flipped and multiplied.
Results are reduced by dividing the top and bottom by their greatest common factor.
Formula
a/b + c/d = (ad + bc)/bd; a/b × c/d = ac/bd; a/b ÷ c/d = ad/bc
Questions people ask
How do I enter a mixed number?
Type the whole number, a space, then the fraction: 2 3/4. For a negative mixed number put the minus sign first: -2 3/4.
Why do I need a common denominator to add fractions?
You can only add pieces of the same size. 1/2 + 1/3 becomes 3/6 + 2/6 = 5/6 once both are expressed in sixths.
How do you divide fractions?
Multiply by the reciprocal of the second fraction. 3/4 ÷ 1/2 = 3/4 × 2/1 = 6/4 = 3/2.
How is the answer simplified?
The numerator and denominator are divided by their greatest common factor. 6/8 has a GCF of 2, so it simplifies to 3/4.