Operations on Rational Numbers

Mathematics — First Preparatory

Multiplication and division

To multiply two fractions, multiply the numerators together and the denominators together: (a/b) × (c/d) = ac/bd.
To divide a fraction by another fraction, multiply by the reciprocal of the second fraction: (a/b) ÷ (c/d) = (a/b) × (d/c).
The sign rules are the same as for integers equal signs give a positive result and different signs give a negative result. The denominator can never be zero, so we can never divide by zero.
Common factors can be cancelled before multiplying to make the calculation easier.

Operations on Rational Numbers · 3 / 7