Решаем пример:
$$\frac{1}{2} - (-\frac{1}{6}) - \frac{1}{3} = \frac{1}{2} + \frac{1}{6} - \frac{1}{3} = \frac{3}{6} + \frac{1}{6} - \frac{2}{6} = \frac{3 + 1 - 2}{6} = \frac{2}{6} = \frac{1}{3}$$
Ответ: $$\frac{1}{3}$$