Answer
(a) $\frac{3}{2}$
(b) $\frac{1}{6}$
Work Step by Step
We find common denominators and reduce:
(a) $\displaystyle \frac{5}{6}+\frac{2}{3}=\frac{5}{6}+\frac{4}{6}=\frac{9}{6}=\frac{3}{2}$
(b) $\displaystyle \frac{5}{6}-\frac{2}{3}=\frac{5}{6}-\frac{4}{6}=\frac{1}{6}$