Решение:
- \( \frac{3}{5} \cdot \frac{3}{7} = \frac{3 \cdot 3}{5 \cdot 7} = \frac{9}{35} \)
- \( \frac{2}{11} \cdot \frac{4}{5} = \frac{2 \cdot 4}{11 \cdot 5} = \frac{8}{55} \)
- \( \frac{3}{5} \cdot \frac{6}{7} = \frac{3 \cdot 6}{5 \cdot 7} = \frac{18}{35} \)
- \( \frac{1}{9} \cdot \frac{4}{7} = \frac{1 \cdot 4}{9 \cdot 7} = \frac{4}{63} \)
- \( \frac{5}{6} \cdot \frac{1}{11} = \frac{5 \cdot 1}{6 \cdot 11} = \frac{5}{66} \)
- \( \frac{3}{4} \cdot \frac{1}{8} = \frac{3 \cdot 1}{4 \cdot 8} = \frac{3}{32} \)
- \( \frac{5}{7} \cdot \frac{5}{6} = \frac{5 \cdot 5}{7 \cdot 6} = \frac{25}{42} \)
- \( \frac{3}{13} \cdot \frac{1}{2} = \frac{3 \cdot 1}{13 \cdot 2} = \frac{3}{26} \)
- \( \frac{2}{5} \cdot \frac{8}{25} = \frac{2 \cdot 8}{5 \cdot 25} = \frac{16}{125} \)
- \( \frac{2}{7} \cdot \frac{2}{5} = \frac{2 \cdot 2}{7 \cdot 5} = \frac{4}{35} \)
- \( \frac{1}{4} : 3 = \frac{1}{4} \cdot \frac{1}{3} = \frac{1 \cdot 1}{4 \cdot 3} = \frac{1}{12} \)
- \( \frac{2}{7} : \frac{4}{7} = \frac{2}{7} \cdot \frac{7}{4} = \frac{2 \cdot 7}{7 \cdot 4} = \frac{14}{28} = \frac{1}{2} \)
- \( 3 : \frac{3}{14} = 3 \cdot \frac{14}{3} = \frac{3 \cdot 14}{3} = 14 \)
- \( \frac{2}{17} \cdot 8 = \frac{2 \cdot 8}{17} = \frac{16}{17} \)
- \( \frac{5}{14} \cdot 3 = \frac{5 \cdot 3}{14} = \frac{15}{14} \)
- \( \frac{4}{27} \cdot \frac{3}{1} \cdot \frac{4 \cdot 3}{27 \cdot 1} = \frac{12}{27} = \frac{4}{9} \)
- \( \frac{6}{7} \cdot 7 = \frac{6 \cdot 7}{7} = 6 \)
- \( \frac{3}{11} \cdot 22 = \frac{3 \cdot 22}{11} = \frac{3 \cdot 2 \cdot 11}{11} = 6 \)
- \( 28 \cdot \frac{3}{7} = \frac{28 \cdot 3}{7} = \frac{4 \cdot 7 \cdot 3}{7} = 12 \)
- \( \frac{2}{5} \cdot \frac{2}{9} = \frac{2 \cdot 2}{5 \cdot 9} = \frac{4}{45} \)
- \( \frac{6}{7} \cdot \frac{9}{2} = \frac{6 \cdot 9}{7 \cdot 2} = \frac{3 \cdot 2 \cdot 9}{7 \cdot 2} = \frac{27}{7} \)
- \( \frac{8}{11} : \frac{3}{4} = \frac{8}{11} \cdot \frac{4}{3} = \frac{8 \cdot 4}{11 \cdot 3} = \frac{32}{33} \)
- \( \frac{10}{81} : \frac{9}{20} = \frac{10}{81} \cdot \frac{20}{9} = \frac{10 \cdot 20}{81 \cdot 9} = \frac{200}{729} \)
- \( \frac{14}{25} : \frac{45}{49} = \frac{14}{25} \cdot \frac{49}{45} = \frac{14 \cdot 49}{25 \cdot 45} = \frac{686}{1125} \)
- \( \frac{12}{55} : \frac{11}{24} = \frac{12}{55} \cdot \frac{24}{11} = \frac{12 \cdot 24}{55 \cdot 11} = \frac{288}{605} \)
- \( \frac{18}{25} : \frac{10}{27} = \frac{18}{25} \cdot \frac{27}{10} = \frac{18 \cdot 27}{25 \cdot 10} = \frac{486}{250} = \frac{243}{125} \)
- \( \frac{34}{39} : \frac{13}{17} = \frac{34}{39} \cdot \frac{17}{13} = \frac{34 \cdot 17}{39 \cdot 13} = \frac{578}{507} \)
- \( \frac{15}{4} \cdot \frac{12}{5} = \frac{15 \cdot 12}{4 \cdot 5} = \frac{3 \cdot 5 \cdot 3 \cdot 4}{4 \cdot 5} = 9 \)
- \( \frac{3}{4} \cdot \frac{7}{8} = \frac{3 \cdot 7}{4 \cdot 8} = \frac{21}{32} \)
Ответ: 1. \( \frac{9}{35} \) 2. \( \frac{8}{55} \) 3. \( \frac{18}{35} \) 4. \( \frac{4}{63} \) 5. \( \frac{5}{66} \) 6. \( \frac{3}{32} \) 7. \( \frac{25}{42} \) 8. \( \frac{3}{26} \) 9. \( \frac{16}{125} \) 10. \( \frac{4}{35} \) 11. \( \frac{1}{12} \) 12. \( \frac{1}{2} \) 13. \( 14 \) 14. \( \frac{16}{17} \) 15. \( \frac{15}{14} \) 16. \( \frac{4}{9} \) 17. \( 6 \) 18. \( 6 \) 19. \( 12 \) 20. \( \frac{4}{45} \) 21. \( \frac{27}{7} \) 22. \( \frac{32}{33} \) 23. \( \frac{200}{729} \) 24. \( \frac{686}{1125} \) 25. \( \frac{288}{605} \) 26. \( \frac{243}{125} \) 27. \( \frac{578}{507} \) 28. \( 9 \) 29. \( \frac{21}{32} \) 30. \( \frac{21}{32} \)