How to use the fraction calculator
Enter the numerator and denominator for each fraction, then choose addition, subtraction, multiplication, or division. Denominators cannot be zero.
Fraction arithmetic
The result is reduced by dividing the numerator and denominator by their greatest common divisor.
Example: Ava adds two recipe quantities
Ava combines 1/2 cup and 1/4 cup. Converting 1/2 to 2/4 gives 2/4 + 1/4 = 3/4 cup. The decimal equivalent is 0.75.
For division, the second fraction is inverted before multiplication. A zero numerator in that second fraction would mean division by zero and has no defined result.
Why addition and subtraction need a common denominator
Fractions can be added or subtracted directly only when they describe equal-sized parts. Converting to a common denominator rewrites both fractions using the same part size before combining the numerators.
Multiplication does not require a common denominator: multiply numerators together and denominators together, then simplify. Division multiplies by the reciprocal of the second fraction.
What it means to simplify a fraction
A fraction is in lowest terms when the numerator and denominator have no common factor greater than 1. Dividing both by their greatest common divisor preserves the value while producing the simplest whole-number form.
A simplified fraction and its decimal equivalent represent the same quantity; the more useful format depends on the task.
Assumptions and limitations
What the estimate assumes
This tool works with numeric fractions, not algebraic expressions.
Fraction Calculator FAQs
How do you add fractions with different denominators?
Rewrite the fractions using a common denominator, add the numerators, then simplify.
How do you divide fractions?
Multiply the first fraction by the reciprocal of the second fraction.
Why can't a denominator be zero?
Division by zero is undefined, so a fraction cannot have a zero denominator.
Does the calculator simplify fractions?
Yes. It reduces the final numerator and denominator by their greatest common divisor.
How do I add fractions with different denominators?
Convert both fractions to a common denominator, add the new numerators, keep the common denominator, and simplify the result.
How do I divide fractions?
Multiply the first fraction by the reciprocal of the second fraction, then simplify. Division by a zero-valued fraction is undefined.
For arithmetic and educational use.