How to use this calculator
- Enter or choose first numerator.
- Enter or choose first denominator.
- Enter or choose operation.
- Enter or choose second numerator.
- Enter or choose second denominator.
- The answer updates as you type. Use Copy result or Share to keep it.
Formula
a/b + c/d = (ad + bc) / bd; a/b × c/d = ac / bd; a/b ÷ c/d = ad / bc
- a, c
- numerators
- b, d
- denominators (not zero)
Worked example
- 1/2 + 1/3 = (1 × 3 + 2 × 1) ÷ (2 × 3).
- = (3 + 2) ÷ 6 = 5/6.
- 5 and 6 share no common factor, so 5/6 is already in lowest terms.
1/2 + 1/3 = 5/6 ≈ 0.8333.
What the result means
To divide by a fraction, multiply by its reciprocal: 3/4 ÷ 3/8 = 3/4 × 8/3 = 2. Improper results such as 7/4 are also shown as mixed numbers (1 3/4).
Assumptions and limits
- Numerators and denominators are whole numbers; negative values are allowed.
- Enter mixed numbers as improper fractions (1 1/2 → 3/2).
Questions
How do I add fractions with different denominators?
Rewrite them over a common denominator. For 1/2 + 1/3, use 6: 3/6 + 2/6 = 5/6.
How do I simplify a fraction?
Divide the top and bottom by their greatest common divisor. 18/24 → divide by 6 → 3/4.