Fraction Calculator: Add, Subtract, Multiply and Divide Fractions
Pick an operation, enter the numerator and denominator of each fraction, and see the simplified result and its decimal.
Updated
Report a problem
Formula
With fractions a/b and c/d (whole numbers, b and d not zero):
- Add:
(a×d + c×b) ÷ (b×d) - Subtract:
(a×d − c×b) ÷ (b×d) - Multiply:
(a×c) ÷ (b×d) - Divide:
(a×d) ÷ (b×c)(c cannot be zero)
The result is then divided top and bottom by their greatest common divisor, and the decimal is numerator ÷ denominator.
Worked example
1/2 + 1/3 = (1×3 + 1×2) ÷ (2×3) = 5/6, already in simplest form, which is 0.833333 as a decimal.
3/4 − 1/6 = (18 − 4) ÷ 24 = 14/24 = 7/12.
Frequently asked questions
How do you add fractions with different denominators?
Rewrite both over a common denominator, add the numerators, then simplify. For 1/2 + 1/3 that is 3/6 + 2/6 = 5/6.
How do you multiply fractions?
Multiply the numerators together and the denominators together, then simplify. 2/3 × 3/4 = 6/12 = 1/2.
How do you divide one fraction by another?
Multiply by the reciprocal of the second fraction. 1/2 ÷ 3/4 = 1/2 × 4/3 = 4/6 = 2/3. You cannot divide by a fraction whose numerator is zero.
How is a fraction simplified?
Divide the numerator and denominator by their greatest common divisor. For 12/18 the greatest common divisor is 6, so it simplifies to 2/3.