How to Calculate with Fractions
A practical guide to fraction arithmetic and entering fractions in a calculator.
Adding and subtracting
Find a common denominator, convert each fraction, then add or subtract the numerators. For example, 1/3 + 1/6 = 2/6 + 1/6 = 1/2.
Multiplying
Multiply numerator by numerator and denominator by denominator. Then reduce the result if possible.
Dividing
To divide by a fraction, multiply by its reciprocal: 2/3 ÷ 4/5 = 2/3 × 5/4 = 5/6.
Entering fractions
In the scientific calculator, type fractions using slash notation such as 3/8. Parentheses remove ambiguity in compound expressions.