135. Выполните действия: a) (1 3/5 + 2 1/5) : 1 9/10 + (1 7/10 - 4/5) : 3/7;

Решение:

a) \( \left(1\frac{3}{5} + 2\frac{1}{5}\right) : 1\frac{9}{10} + \left(1\frac{7}{10} - \frac{4}{5}\right) : \frac{3}{7} \)

1. \( 1\frac{3}{5} + 2\frac{1}{5} = \frac{8}{5} + \frac{11}{5} = \frac{19}{5} \)
2. \( \frac{19}{5} : 1\frac{9}{10} = \frac{19}{5} : \frac{19}{10} = \frac{19}{5} \times \frac{10}{19} = \frac{10}{5} = 2 \)
3. \( 1\frac{7}{10} - \frac{4}{5} = \frac{17}{10} - \frac{8}{10} = \frac{9}{10} \)
4. \( \frac{9}{10} : \frac{3}{7} = \frac{9}{10} \times \frac{7}{3} = \frac{3 \times 7}{10} = \frac{21}{10} = 2\frac{1}{10} \)
5. \( 2 + 2\frac{1}{10} = 4\frac{1}{10} \)

Ответ: 4 1/10.