To add or subtract rational expressions with unlike denominators, first find the LCM of the denominator. The LCM of the denominators of fraction or rational expressions is also called least common denominator , or LCD. So 1/2 and 5/6 should have same denominator,
[tex] \frac{1}{2} \times3 = \frac{3}{6} [/tex]
so now simply add
[tex] \frac{3}{6} + \frac{5}{6} = \frac{8}{6} \: or \: \frac{4}{3}\: or \: 1 \frac{1}{3} [/tex]
