OPERATIONS WITH RATIONAL NUMBERS
(a) Addition and Subtraction
Use a common denominator.
Example
\frac{2}{3} + \frac{1}{6}LCM of 3 and 6 = 6
= \frac{4}{6} + \frac{1}{6} = \frac{5}{6}(b) Multiplication
Multiply numerators and denominators.
Example
\frac{3}{4} \times \frac{2}{5} = \frac{6}{20} = \frac{3}{10}(c) Division
Multiply by the reciprocal.
Example
\frac{4}{5} \div \frac{2}{3} = \frac{4}{5} \times \frac{3}{2} = \frac{12}{10} = \frac{6}{5}