Ты просишь меня найти значение выражений с дробями.

Конечно, давай решим эти примеры по порядку! 1. $$ \frac{7}{8} \cdot \frac{5}{6} \cdot \frac{9}{20} = \frac{7 \cdot 5 \cdot 9}{8 \cdot 6 \cdot 20} = \frac{315}{960} = \frac{21}{64} $$ 2. $$ \frac{5}{8} - \frac{9}{14} \cdot \frac{7}{12} = \frac{5}{8} - \frac{9 \cdot 7}{14 \cdot 12} = \frac{5}{8} - \frac{63}{168} = \frac{5}{8} - \frac{3}{8} = \frac{2}{8} = \frac{1}{4} $$ 3. $$ \frac{8}{9} - \frac{5}{12} : \frac{8}{15} = \frac{8}{9} - \frac{5}{12} \cdot \frac{15}{8} = \frac{8}{9} - \frac{5 \cdot 15}{12 \cdot 8} = \frac{8}{9} - \frac{75}{96} = \frac{8}{9} - \frac{25}{32} = \frac{256}{288} - \frac{225}{288} = \frac{31}{288} $$ 4. $$ \frac{10}{21} : \frac{4}{15} \cdot \frac{5}{14} = \frac{10}{21} \cdot \frac{15}{4} \cdot \frac{5}{14} = \frac{10 \cdot 15 \cdot 5}{21 \cdot 4 \cdot 14} = \frac{750}{1176} = \frac{125}{196} $$ 5. $$ \frac{2}{9} + \frac{4}{7} : \frac{9}{28} = \frac{2}{9} + \frac{4}{7} \cdot \frac{28}{9} = \frac{2}{9} + \frac{4 \cdot 28}{7 \cdot 9} = \frac{2}{9} + \frac{112}{63} = \frac{2}{9} + \frac{16}{9} = \frac{18}{9} = 2 $$ 6. $$ \frac{9}{11} + \frac{3}{5} : \frac{11}{40} = \frac{9}{11} + \frac{3}{5} \cdot \frac{40}{11} = \frac{9}{11} + \frac{3 \cdot 40}{5 \cdot 11} = \frac{9}{11} + \frac{120}{55} = \frac{9}{11} + \frac{24}{11} = \frac{33}{11} = 3 $$ 7. $$ \frac{3}{7} + \frac{5}{8} : \frac{7}{40} = \frac{3}{7} + \frac{5}{8} \cdot \frac{40}{7} = \frac{3}{7} + \frac{5 \cdot 40}{8 \cdot 7} = \frac{3}{7} + \frac{200}{56} = \frac{3}{7} + \frac{25}{7} = \frac{28}{7} = 4 $$ 8. $$ \frac{3}{5} + \frac{2}{3} : \frac{5}{33} = \frac{3}{5} + \frac{2}{3} \cdot \frac{33}{5} = \frac{3}{5} + \frac{2 \cdot 33}{3 \cdot 5} = \frac{3}{5} + \frac{66}{15} = \frac{3}{5} + \frac{22}{5} = \frac{25}{5} = 5 $$ 9. $$ 2 \frac{5}{8} : \frac{3}{4} + \frac{1}{2} = \frac{21}{8} : \frac{3}{4} + \frac{1}{2} = \frac{21}{8} \cdot \frac{4}{3} + \frac{1}{2} = \frac{21 \cdot 4}{8 \cdot 3} + \frac{1}{2} = \frac{84}{24} + \frac{1}{2} = \frac{7}{2} + \frac{1}{2} = \frac{8}{2} = 4 $$ 10. $$ 4 \frac{1}{6} : \frac{5}{2} + \frac{1}{3} = \frac{25}{6} : \frac{5}{2} + \frac{1}{3} = \frac{25}{6} \cdot \frac{2}{5} + \frac{1}{3} = \frac{25 \cdot 2}{6 \cdot 5} + \frac{1}{3} = \frac{50}{30} + \frac{1}{3} = \frac{5}{3} + \frac{1}{3} = \frac{6}{3} = 2 $$ 11. $$ 2 \frac{1}{16} : \frac{3}{4} + \frac{1}{4} = \frac{33}{16} : \frac{3}{4} + \frac{1}{4} = \frac{33}{16} \cdot \frac{4}{3} + \frac{1}{4} = \frac{33 \cdot 4}{16 \cdot 3} + \frac{1}{4} = \frac{132}{48} + \frac{1}{4} = \frac{11}{4} + \frac{1}{4} = \frac{12}{4} = 3 $$ 12. $$ 3 \frac{11}{15} : \frac{4}{5} + \frac{1}{3} = \frac{56}{15} : \frac{4}{5} + \frac{1}{3} = \frac{56}{15} \cdot \frac{5}{4} + \frac{1}{3} = \frac{56 \cdot 5}{15 \cdot 4} + \frac{1}{3} = \frac{280}{60} + \frac{1}{3} = \frac{14}{3} + \frac{1}{3} = \frac{15}{3} = 5 $$ 13. $$ 1 - \frac{3}{8} \cdot \frac{3}{5} = 1 - \frac{3 \cdot 3}{8 \cdot 5} = 1 - \frac{9}{40} = \frac{40}{40} - \frac{9}{40} = \frac{31}{40} $$ 14. $$ 1 - \frac{4}{5} : 2 \frac{2}{9} = 1 - \frac{4}{5} : \frac{20}{9} = 1 - \frac{4}{5} \cdot \frac{9}{20} = 1 - \frac{4 \cdot 9}{5 \cdot 20} = 1 - \frac{36}{100} = 1 - \frac{9}{25} = \frac{25}{25} - \frac{9}{25} = \frac{16}{25} $$ Надеюсь, теперь тебе стало понятнее, как решать такие примеры! Если что, спрашивай ещё.