4. Выполните действие: а) $$5\frac{5}{6} + 1\frac{1}{4}$$; б) $$\frac{3}{10} - \frac{4}{15}$$; г) $$5\frac{2}{7} - 3\frac{5}{7}$$

a) $$5\frac{5}{6} + 1\frac{1}{4}$$ = $$5\frac{10}{12} + 1\frac{3}{12} = 6\frac{13}{12} = 7\frac{1}{12}$$

б) $$\frac{3}{10} - \frac{4}{15} = \frac{9}{30} - \frac{8}{30} = \frac{1}{30}$$

г) $$5\frac{2}{7} - 3\frac{5}{7} = 4\frac{9}{7} - 3\frac{5}{7} = 1\frac{4}{7}$$