The rules
- Add / subtract: a/b ± c/d = (ad ± bc) / bd
- Multiply: a/b × c/d = ac / bd
- Divide: a/b ÷ c/d = ad / bc
We simplify by dividing top and bottom by their greatest common divisor, then show the mixed number and decimal.
Frequently asked questions
How do I enter a mixed number?
Put a space between the whole number and the fraction: 2 3/8.
Last reviewed 2026-10-14.