How to calculate fractions
a/b + c/d = (ad + bc) / bd a/b × c/d = ac / bd a/b ÷ c/d = ad / bc
Worked example. Result: 1.41666667.
Example inputs — Calculate: Fraction arithmetic; First numerator: 3; First denominator: 4; Operation: + Add; Second numerator: 2; Second denominator: 3. Starting values are illustrative.
17/12 = 1 5/12
From George Guju, founder of Calculyn · Educational calculator guidance, not professional advice.
How it works
Choose arithmetic, mixed numbers, simplification or decimal conversion. Fractions use exact integer arithmetic, including big numbers; the decimal display is an approximation. Denominators and a divisor fraction cannot be zero.
Assumptions & limitations
- Results are rounded for display.
Formula and assumptions reviewed October 2026 by the Calculyn team. How we build our calculators
Frequently asked questions
What is a mixed number?
A whole number plus a proper fraction, like 1 5/12.