Решение:
a) \(-\frac{1}{6} + \frac{2}{3} = -\frac{1}{6} + \frac{4}{6} = \frac{3}{6} = \frac{1}{2}\)
б) \(-\frac{4}{5} + (\frac{1}{10}) = -\frac{8}{10} + \frac{1}{10} = -\frac{7}{10}\)
в) \(\frac{5}{9} + (-\frac{1}{3}) = \frac{5}{9} - \frac{3}{9} = \frac{2}{9}\)