Fraction Calculator
Add, subtract, multiply, and divide fractions — simplified automatically.
How fraction arithmetic works
Addition/Subtraction — find a common denominator: a/b ± c/d = (a×d ± c×b) / (b×d), then simplify.
Multiplication — multiply numerators and denominators: (a/b) × (c/d) = (a×c) / (b×d), then simplify.
Division — multiply by the reciprocal: (a/b) ÷ (c/d) = (a×d) / (b×c), then simplify.
Simplification uses the GCD (Greatest Common Divisor) to reduce the result to lowest terms.
Frequently asked questions
Can I enter negative fractions?
Yes. Enter a negative numerator (e.g. −3 over 4) to represent a negative fraction. The calculator handles signs correctly and always places the negative sign on the numerator in the result.
What does "simplify to lowest terms" mean?
A fraction is in lowest terms when the numerator and denominator share no common factor other than 1. For example, 6/8 simplifies to 3/4 because GCD(6,8) = 2.
