How this calculation works
Enter each fraction as an integer numerator and denominator, then choose the operation. The result is reduced to lowest terms with a positive denominator. The fraction preserves the exact rational answer; the decimal is an approximation when the decimal expansion repeats.
Worked example
This example uses illustrative inputs. Your current result is shown above.
For 1/2 + 1/3, the common denominator is 6: (1 × 3 + 1 × 2)/(2 × 3) = (3 + 2)/6 = 5/6. Its decimal is approximately 0.8333333333.
Assumptions and limits
- Numerators and denominators must be whole numbers, and denominators cannot be zero.
- Division also requires the second numerator to be nonzero.
- Mixed numbers must first be written as improper fractions; enter 7/3 rather than “2 1/3”.
Questions people ask
Why does a negative denominator move to the top?
The sign belongs to the fraction as a whole. Writing −1/2 rather than 1/−2 makes the reduced result consistent; two negative signs cancel.
Why does the decimal stop while the fraction stays exact?
A value such as 1/3 has an infinite repeating decimal. The decimal output is rounded, but the reduced numerator and denominator retain the exact rational result.