Fraction Calculator: instructions, examples and limits

What it does

Uses common denominators for addition/subtraction and cross products for multiplication/division, then reduces by GCD.

Use the fraction calculator to add, subtract, multiply or divide rational values while keeping the reduced numerator and denominator visible.

How to use it

1. 1

   Enter two numerators and denominators using non-zero denominators.

2. 2

   Choose an operation and run the calculation.

3. 3

   Check the reduced result and convert it to a decimal only when that form is useful for your next step.

How the result is produced

Uses common denominators for addition/subtraction and cross products for multiplication/division, then reduces by GCD.

Important limits

Exact safe-integer arithmetic only. Zero denominators and overflow are rejected.

Checks before sharing or relying on the result

• The sign is normalised and the result is reduced by the greatest common divisor.
• A zero denominator is invalid rather than treated as infinity.
• Very large values may exceed safe integer precision; the tool refuses unsafe input.

Choosing the next step

Enter values in the units and convention named by the page, then compare the displayed formula with your question. For money, change the assumptions rather than treating an estimate as an offer; for statistics, decide whether the data represents a sample or a full population.