Fraction Calculator

Add, subtract, multiply, or divide fractions. Get simplified results, mixed numbers, and decimal equivalents.

This calculator runs one of four operations — Add, Subtract, Multiply, or Divide — on two fractions, choosing the formula from the Operation dropdown (lines 76-95). Add and Subtract first find a common denominator via lcm(Denominator 1, Denominator 2) and rebuild both numerators over it (lines 77-82); Multiply and Divide instead combine numerators and denominators directly (lines 84-91), so they never need a common denominator at all. All four numeric inputs — both numerators and both denominators — feed the Decimal and Percentage outputs at the calculator's default Add operation, but not by a comparable amount across the two fractions: Numerator 1 and Denominator 1 move the result by a comparable amount to each other, and Numerator 2 and Denominator 2 likewise move it by a comparable amount to each other, but Fraction 2's pair (1/3) moves it only about half as much as Fraction 1's pair (3/4) does, because 1/3 contributes less to the 13/12 sum than 3/4 does. Dividing by zero is guarded specifically: only Operation = Divide with Numerator 2 exactly equal to 0 (line 24) returns "Cannot divide by zero"; a nonzero-but-tiny Numerator 2 skips that guard entirely and produces a very large finite result instead of an error. The Result fraction is simplified using a greatest-common-divisor helper that rounds its two arguments to the nearest integer before dividing (line 4), while the raw numerator/denominator arithmetic above it uses your exact typed values — so a non-integer numerator or denominator is handled inconsistently between the main calculation and the simplification step that follows it. This calculator does not validate that a typed value stays a whole number; despite Denominator 1 having a minimum of 1, nothing stops a decimal value from being entered and carried through both of those mismatched code paths.