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Adding Fractions Calculator

Estimate the sum of two, three, four, or five fractions using the adding fractions calculator.

Clear
Result5/6in lowest terms
Mixed number5/6
Decimal0.83333333
Percentage83.333333%

Adding step by step

Problem1/2 + 1/3
Common denominator6
Result before reducing5/6
Lowest terms5/6

The method

a/b + c/d = (ad + cb) / bd

The rules in one place

  • Adding and subtracting needs a common denominator first. The lowest common denominator keeps the numbers smallest, but any common denominator works.
  • Multiplying needs no common denominator at all — multiply across the top and across the bottom.
  • Dividing means multiplying by the reciprocal: flip the second fraction and multiply.
  • Reducing divides top and bottom by their greatest common divisor. It never changes the value.

Why lowest terms matter

6/8 and 3/4 are the same number, but 3/4 is easier to compare, easier to check and conventional in an answer. Reducing also keeps later arithmetic small: multiplying unreduced fractions makes the numbers grow fast, and cancelling first avoids that.