5. Выполните действие: a) $$\frac{-1}{6} + \frac{2}{3}$$; б) $$\frac{-4}{5} + (\frac{-1}{10})$$; в) $$3\frac{3}{8} - \frac{3}{4}$$; д) $$-0,25 - (-1,2)$$; г) $$1,2 - 12,3$$; е) $$-17,9 + 3,12$$.

a) $$\frac{-1}{6} + \frac{2}{3} = \frac{-1}{6} + \frac{4}{6} = \frac{3}{6} = \frac{1}{2} = 0,5$$ б) $$\frac{-4}{5} + (\frac{-1}{10}) = \frac{-8}{10} - \frac{1}{10} = \frac{-9}{10} = -0,9$$ в) $$3\frac{3}{8} - \frac{3}{4} = \frac{27}{8} - \frac{6}{8} = \frac{21}{8} = 2\frac{5}{8} = 2,625$$ г) $$1,2 - 12,3 = -11,1$$ д) $$-0,25 - (-1,2) = -0,25 + 1,2 = 0,95$$ е) $$-17,9 + 3,12 = -14,78$$