Вычисляем

1. а) $$4\frac{4}{7}+12\frac{5}{7} = (4+12) + (\frac{4}{7}+\frac{5}{7}) = 16 + \frac{9}{7} = 16 + 1\frac{2}{7} = 17\frac{2}{7}$$

   Ответ: $$17\frac{2}{7}$$

2. б) $$9\frac{8}{15}+6\frac{13}{15} = (9+6) + (\frac{8}{15}+\frac{13}{15}) = 15 + \frac{21}{15} = 15 + 1\frac{6}{15} = 16\frac{6}{15} = 16\frac{2}{5}$$

   Ответ: $$16\frac{2}{5}$$

3. в) $$5\frac{4}{7}-1\frac{5}{7} = 5\frac{4}{7}-1\frac{5}{7} = \frac{39}{7} - \frac{12}{7} = \frac{27}{7} = 3\frac{6}{7}$$

   Ответ: $$3\frac{6}{7}$$

4. г) $$4\frac{8}{15}-2\frac{13}{15} = 4\frac{8}{15}-2\frac{13}{15} = \frac{68}{15} - \frac{43}{15} = \frac{25}{15} = \frac{5}{3} = 1\frac{2}{3}$$

   Ответ: $$1\frac{2}{3}$$