Add, subtract, multiply or divide two fractions and get the reduced, decimal and mixed-number forms.
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Addition and subtraction convert both fractions to a common denominator first, then combine the numerators. Multiplication multiplies straight across, numerator times numerator, denominator times denominator. Division flips the second fraction and multiplies. Every result is then reduced by dividing both the numerator and denominator by their greatest common divisor, so you always see the simplest possible form.
The Result row is the reduced fraction, the exact value with no rounding anywhere in it. The Decimal row rounds that same value to four places, which is close enough for most purposes but is technically an approximation the moment the true decimal repeats, like 1/3 becoming 0.3333 instead of going on forever. The Mixed number row splits an improper fraction, one where the numerator is larger than the denominator, into a whole number plus a proper fraction; if the result is already proper, that row just repeats the Result row since there is nothing left to split out.
These come up often enough that memorizing a few saves time double-checking a calculator:
These are exact mathematical facts, not a convention that varies by textbook or region.
Adding 1/2 and 1/3: the common denominator is 6, so the fractions become 3/6 and 2/6. Add the numerators, 3 plus 2, for 5/6, which is already in lowest terms since 5 and 6 share no common factor above 1. As a decimal that is 0.8333, and since 5 is smaller than 6, there is no whole-number part to separate out, so the mixed-number form matches the fraction form exactly.
The Result field always shows the reduced fraction first, since that is the exact value; decimals are often a rounded approximation. Check the Decimal row underneath if a decimal is what you actually need.
Division by zero is undefined in ordinary arithmetic, so the calculator will not return a result for that field. Double-check that both denominators are nonzero before reading the output.
Enter the negative sign on the numerator (for example, -1 over 2). The calculator normalizes the sign so the denominator always displays as positive, which is the standard way to write a negative fraction.
If the result is already a proper fraction, meaning the numerator is smaller than the denominator, there is no whole-number part to separate out, so the mixed number row matches the fraction row exactly.