Math
Fraction Calculator
Add, subtract, multiply and divide fractions with the steps
Enter two fractions in the fraction calculator and choose the operation. We give you the answer in simplest form and show how to get there.
The key idea
Adding fractions is not adding tops and bottoms: it is matching denominators
3/4 + 5/6 is not 8/10. With the common denominator 12, the least common multiple of 4 and 6, you get 9/12 + 10/12 = 19/12, which is 1 7/12 or 1.5833. Adding numerators and denominators separately is a very common mistake.
How it is calculated
- Add and subtract
- Rewrite both fractions with a common denominator (the least common multiple of the denominators) and add or subtract the numerators.
- Multiply
- Numerator times numerator and denominator times denominator.
- Divide
- Cross-multiply (which is the same as multiplying by the reciprocal of the second fraction).
Finally, simplify by dividing the numerator and the denominator by their greatest common factor.
Worked example
3/4 + 5/6: the LCM of 4 and 6 is 12 → 9/12 + 10/12 = 19/12 = 1 7/12 ≈ 1.5833.
Common questions
Frequently asked questions
How do I enter a whole number?
As a fraction with a denominator of 1: 3 is 3/1.
How do I enter a mixed number like 2 1/3?
Convert it to an improper fraction first: (2 × 3 + 1)/3 = 7/3. Multiply the whole number by the denominator, add the numerator and keep the same denominator.
How do I simplify a fraction?
Divide the numerator and the denominator by their greatest common factor: 18/24 divided by 6 is 3/4. The calculator does it for you and tells you which number it divided by.
How do I divide fractions?
Multiply the first fraction by the reciprocal of the second: 3/4 ÷ 5/6 = 3/4 × 6/5 = 18/20 = 9/10. It is the same as cross-multiplying.
Can I use negative fractions?
Yes: enter the numerator as a negative number, for example -3 over 4. In the result, the sign always goes in the numerator.
How do I convert a fraction to a decimal?
Divide the numerator by the denominator: 19/12 = 1.5833… The calculator also gives you the decimal for every result.
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