Add, subtract, multiply or divide two fractions and receive a simplified exact fraction plus an approximate decimal. Enter whole-number numerators and non-zero denominators.
a/b + c/d = (ad+bc)/bd. For subtraction replace + with −. Multiplication gives ac/bd; division gives ad/bc. Reduce numerator and denominator by their greatest common divisor.
1/2 + 1/3 = (3+2)/6 = 5/6 ≈ 0.833333. For 2/3 ÷ 4/5, multiply 2/3 by 5/4 to obtain 10/12 = 5/6.
A denominator cannot be zero and division by a zero fraction is undefined. Large integers are rejected if intermediate arithmetic cannot remain exact in JavaScript. Enter a mixed number as an improper fraction: 1½ becomes 3/2.
Editorial responsibility: Nicolas Belotti · Methods and testing · Report an error
English edition: 16 September 2026.