17. Выполните действие: a) \( \frac{5}{6} + \frac{1}{4} \) b) \( \frac{3}{10} - \frac{4}{15} \) в) \( \frac{7}{8} - \frac{5}{6} \) г) \( 5 - 3 \frac{2}{7} \) д) \( \frac{4}{9} \cdot \frac{3}{8} \) e) \( \frac{5}{8} : \frac{9}{10} \) ж) \( 2 \frac{6}{7} \cdot \frac{3}{13} \) 3) \( 6 \frac{1}{5} \cdot 10 \)

Решение:

1. а) \( \frac{5}{6} + \frac{1}{4} = \frac{10}{12} + \frac{3}{12} = \frac{13}{12} = 1 \frac{1}{12} \)
2. б) \( \frac{3}{10} - \frac{4}{15} = \frac{9}{30} - \frac{8}{30} = \frac{1}{30} \)
3. в) \( \frac{7}{8} - \frac{5}{6} = \frac{21}{24} - \frac{20}{24} = \frac{1}{24} \)
4. г) \( 5 - 3 \frac{2}{7} = 5 - \frac{23}{7} = \frac{35}{7} - \frac{23}{7} = \frac{12}{7} = 1 \frac{5}{7} \)
5. д) \( \frac{4}{9} \cdot \frac{3}{8} = \frac{4 \cdot 3}{9 \cdot 8} = \frac{12}{72} = \frac{1}{6} \)
6. е) \( \frac{5}{8} : \frac{9}{10} = \frac{5}{8} \cdot \frac{10}{9} = \frac{5 \cdot 10}{8 \cdot 9} = \frac{50}{72} = \frac{25}{36} \)
7. ж) \( 2 \frac{6}{7} \cdot \frac{3}{13} = \frac{20}{7} \cdot \frac{3}{13} = \frac{20 \cdot 3}{7 \cdot 13} = \frac{60}{91} \)
8. з) \( 6 \frac{1}{5} \cdot 10 = \frac{31}{5} \cdot 10 = \frac{31 \cdot 10}{5} = 31 \cdot 2 = 62 \)

Ответ: а) \( 1 \frac{1}{12} \); б) \( \frac{1}{30} \); в) \( \frac{1}{24} \); г) \( 1 \frac{5}{7} \); д) \( \frac{1}{6} \); е) \( \frac{25}{36} \); ж) \( \frac{60}{91} \); з) 62.