Вычислите: 5/7 · 21/15 · 9/24; 4/5 · 8/10 · 20/2; 6/7 · 3/9 · 28/30; 40/50 · 20/5 · 3/4; 17/20 · 10/34 · 5/2; 15/20 · 150/200 · 2/3; 14/63 · 18/28 · 2/6; 77/25 · 11/13 · 65/7; 81/90 · 2/3 · 18/20; 42/60 · 7/12 · 3/21.

1. \(\frac{5}{7}\cdot\frac{21}{15}\cdot\frac{9}{24}=\frac{3}{8}\)
2. \(\frac{4}{5}\cdot\frac{8}{10}\cdot\frac{20}{2}=\frac{32}{5}\)
3. \(\frac{6}{7}\cdot\frac{3}{9}\cdot\frac{28}{30}=\frac{4}{15}\)
4. \(\frac{40}{50}\cdot\frac{20}{5}\cdot\frac{3}{4}=\frac{12}{5}\)
5. \(\frac{17}{20}\cdot\frac{10}{34}\cdot\frac{5}{2}=\frac{5}{8}\)
6. \(\frac{15}{20}\cdot\frac{150}{200}\cdot\frac{2}{3}=\frac{3}{8}\)
7. \(\frac{14}{63}\cdot\frac{18}{28}\cdot\frac{2}{6}=\frac{1}{21}\)
8. \(\frac{77}{25}\cdot\frac{11}{13}\cdot\frac{65}{7}=\frac{121}{5}\)
9. \(\frac{81}{90}\cdot\frac{2}{3}\cdot\frac{18}{20}=\frac{27}{50}\)
10. \(\frac{42}{60}\cdot\frac{7}{12}\cdot\frac{3}{21}=\frac{7}{120}\)

Ответ: 3/8; 32/5; 4/15; 12/5; 5/8; 3/8; 1/21; 121/5; 27/50; 7/120.