The fraction 12/18 and the fraction 2/3 are the same amount of pizza — reducing (simplifying) just writes it in lowest terms, where the numerator and denominator share no common divisor but 1. The method: divide top and bottom by their greatest common divisor. For 12/18, the GCD is 6, so 12 ÷ 6 = 2 and 18 ÷ 6 = 3, giving 2/3. Teachers demand reduced answers, carpenters read 2/3 of an inch faster than 12/18, and every fraction algorithm downstream runs cleaner on small numbers.

Finding the GCD is the only hard part: list divisors, or use Euclid's algorithm of repeated remainders for big numbers (GCD(1071, 462) = 21). A fraction already in lowest terms — like 7/11 — reduces to itself, which is a valid answer, not a failure. This calculator performs one reduction division at a time: type the numerator in the Variable A box (12) and 1 ÷ GCD in the Variable B box (1 ÷ 6 ≈ 0.16667). The Result box shows 2, the reduced numerator. Repeat with the denominator in A (18) to get 3, completing 2/3. Confirm by checking that 2 and 3 share no divisor but 1.

With the pre-filled defaults — Variable A 10, Variable B 5 — the Reducing Fractions Calculator returns Result 50.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.