About fraction calculator
Fractions can be added, subtracted, multiplied and divided with simple rules. The calculator does the steps and simplifies the result.
The rules
- Add or subtract: make the denominators equal, then add the numerators. 1/4 + 1/6 = 3/12 + 2/12 = 5/12.
- Multiply: multiply tops and bottoms. 2/3 × 3/5 = 6/15 = 2/5.
- Divide: flip the second fraction and multiply. 1/2 ÷ 3/4 = 1/2 × 4/3 = 2/3.
Simplifying
Divide the numerator and denominator by their greatest common divisor to reach the lowest terms.
A worked example
3/4 − 2/5 uses a common denominator of 20: 15/20 − 8/20 = 7/20. For division, 5/6 ÷ 5/12 becomes 5/6 × 12/5 = 60/30, which simplifies to 2. A mixed number such as 1 1/2 is first written as 3/2.
Fractions and decimals
Divide the top by the bottom to get a decimal: 7/20 is 0.35. Repeating decimals such as 1/3 = 0.333… are easier to keep as fractions.
