Subtracting Fractions Calculator
The subtracting fractions calculator helps you understand how to solve fraction subtraction problems.
Result1/6in lowest terms
Mixed number1/6
Decimal0.16666667
Percentage16.666667%
Subtracting step by step
| Problem | 1/2 − 1/3 |
| Common denominator | 6 |
| Result before reducing | 1/6 |
| Lowest terms | 1/6 |
The method
a/b − c/d = (ad − cb) / bd
The rules in one place
- Adding and subtracting needs a common denominator first. The lowest common denominator keeps the numbers smallest, but any common denominator works.
- Multiplying needs no common denominator at all — multiply across the top and across the bottom.
- Dividing means multiplying by the reciprocal: flip the second fraction and multiply.
- Reducing divides top and bottom by their greatest common divisor. It never changes the value.
Why lowest terms matter
6/8 and 3/4 are the same number, but 3/4 is easier to compare, easier to check and conventional in an answer. Reducing also keeps later arithmetic small: multiplying unreduced fractions makes the numbers grow fast, and cancelling first avoids that.