How do you add fractions with different denominators?

Find a common denominator (the least common multiple of the two denominators), rename each fraction with it, add the numerators and keep the denominator, then simplify.

Do you need a common denominator to multiply fractions?

No. Multiply the numerators together and the denominators together, then simplify.

How do you divide fractions?

Keep the first fraction, change the division to multiplication, and flip the second fraction. Then multiply and simplify.

Can I enter mixed numbers?

Yes. Type the whole number in the left box and the fraction part in the top and bottom boxes, for example 2 and 1/4 for 2 1/4.

free tool

Fraction calculator with steps

Add, subtract, multiply or divide fractions and mixed numbers. Every step is shown, the answer is simplified, and you also get the mixed number and the decimal.

Leave the left box empty for a plain fraction, or type a whole number for a mixed number (like 2 1/4).

2/3 + 3/4 = 1 5/12

As a decimal: 1.4167

Find a common denominator: the least common multiple of 3 and 4 is 12.
Rename both fractions: 2/3 = 8/12 (× 4) and 3/4 = 9/12 (× 3).
Add the numerators: 8 + 9 = 17, giving 17/12.
17/12 is already in simplest form.
As a mixed number: 17/12 = 1 5/12.

How the calculator works

Type two fractions, choose an operation, and the answer appears with every step written out. Mixed numbers are turned into improper fractions first, the answer is always simplified, and an answer bigger than one is also shown as a mixed number and a decimal.

Adding and subtracting: finds the least common denominator, renames both fractions, then adds or subtracts the numerators.
Multiplying: multiplies the numerators and the denominators, then simplifies.
Dividing: flips the second fraction (its reciprocal) and multiplies.
Simplifying: divides the top and bottom by their greatest common factor.

Use it to check, not to skip the thinking

A calculator that shows steps is most useful after a child has tried a question on paper. Compare their working with the steps here and look for the first line that is different. That one line is usually the whole lesson: a denominator that was added, a fraction that was not flipped, or a forgotten simplify.

Worked example

2/3 + 3/4: the least common multiple of 3 and 4 is 12. Rename 2/3 as 8/12 and 3/4 as 9/12. Add the numerators: 8 + 9 = 17, so the answer is 17/12, which is 1 5/12 as a mixed number and about 1.4167 as a decimal.

Questions people ask

How do you add fractions with different denominators?: Find a common denominator (the least common multiple of the two denominators), rename each fraction with it, add the numerators and keep the denominator, then simplify.
Do you need a common denominator to multiply fractions?: No. Multiply the numerators together and the denominators together, then simplify.
How do you divide fractions?: Keep the first fraction, change the division to multiplication, and flip the second fraction. Then multiply and simplify.
Can I enter mixed numbers?: Yes. Type the whole number in the left box and the fraction part in the top and bottom boxes, for example 2 and 1/4 for 2 1/4.

Practice each step

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