Вопрос:

Solve the following multiplication problems: 1) \(\frac{1}{3} \cdot \frac{1}{3}\) 2) \(\frac{2}{5} \cdot \frac{3}{4}\) 3) \(\frac{3}{7} \cdot \frac{2}{5}\) 4) \(\frac{1}{6} \cdot \frac{5}{7}\) 5) \(\frac{4}{7} \cdot \frac{4}{40}\) 6) \(\frac{2}{3} \cdot \frac{3}{8}\) 7) \(\frac{15}{16} \cdot \frac{8}{25}\) 8) \(\frac{4}{5} \cdot \frac{3}{7}\) 9) \(\frac{5}{11} \cdot \frac{6}{6}\) 10) \(\frac{4}{17} \cdot \frac{51}{40}\) 11) \(\frac{3}{10} \cdot \frac{20}{33}\) 12) \(\frac{5}{6} \cdot \frac{6}{5}\) 13) \(\frac{3}{7} \cdot \frac{2}{6}\) 14) \(\frac{8}{3} \cdot \frac{7}{15}\) 15) \(\frac{11}{26} \cdot \frac{13}{55}\) 16) \(\frac{2}{9} \cdot \frac{3}{7}\) 17) \(\frac{6}{7} \cdot \frac{2}{7}\) 18) \(\frac{45}{57} \cdot \frac{23}{19}\) 19) \(\frac{20}{42} \cdot \frac{73}{73}\) 20) \(\frac{8}{16} \cdot \frac{13}{26}\)

Ответ:

Решение:

Для решения примеров будем использовать правило умножения дробей: \( \frac{a}{b} \cdot \frac{c}{d} = \frac{a \cdot c}{b \cdot d} \). Сокращаем, где возможно.

  1. \( \frac{1}{3} \cdot \frac{1}{3} = \frac{1 \cdot 1}{3 \cdot 3} = \frac{1}{9} \)
  2. \( \frac{2}{5} \cdot \frac{3}{4} = \frac{2 \cdot 3}{5 \cdot 4} = \frac{6}{20} = \frac{3}{10} \)
  3. \( \frac{3}{7} \cdot \frac{2}{5} = \frac{3 \cdot 2}{7 \cdot 5} = \frac{6}{35} \)
  4. \( \frac{1}{6} \cdot \frac{5}{7} = \frac{1 \cdot 5}{6 \cdot 7} = \frac{5}{42} \)
  5. \( \frac{4}{7} \cdot \frac{4}{40} = \frac{4}{7} \cdot \frac{1}{10} = \frac{4 \cdot 1}{7 \cdot 10} = \frac{4}{70} = \frac{2}{35} \)
  6. \( \frac{2}{3} \cdot \frac{3}{8} = \frac{2 \cdot 3}{3 \cdot 8} = \frac{6}{24} = \frac{1}{4} \)
  7. \( \frac{15}{16} \cdot \frac{8}{25} = \frac{15 \cdot 8}{16 \cdot 25} = \frac{3 \cdot 1}{2 \cdot 5} = \frac{3}{10} \)
  8. \( \frac{4}{5} \cdot \frac{3}{7} = \frac{4 \cdot 3}{5 \cdot 7} = \frac{12}{35} \)
  9. \( \frac{5}{11} \cdot \frac{6}{6} = \frac{5}{11} \cdot 1 = \frac{5}{11} \)
  10. \( \frac{4}{17} \cdot \frac{51}{40} = \frac{4 \cdot 51}{17 \cdot 40} = \frac{1 \cdot 3}{1 \cdot 10} = \frac{3}{10} \)
  11. \( \frac{3}{10} \cdot \frac{20}{33} = \frac{3 \cdot 20}{10 \cdot 33} = \frac{1 \cdot 2}{1 \cdot 11} = \frac{2}{11} \)
  12. \( \frac{5}{6} \cdot \frac{6}{5} = 1 \)
  13. \( \frac{3}{7} \cdot \frac{2}{6} = \frac{3}{7} \cdot \frac{1}{3} = \frac{3 \cdot 1}{7 \cdot 3} = \frac{1}{7} \)
  14. \( \frac{8}{3} \cdot \frac{7}{15} = \frac{8 \cdot 7}{3 \cdot 15} = \frac{56}{45} \)
  15. \( \frac{11}{26} \cdot \frac{13}{55} = \frac{11 \cdot 13}{26 \cdot 55} = \frac{1 \cdot 1}{2 \cdot 5} = \frac{1}{10} \)
  16. \( \frac{2}{9} \cdot \frac{3}{7} = \frac{2 \cdot 3}{9 \cdot 7} = \frac{2}{3 \cdot 7} = \frac{2}{21} \)
  17. \( \frac{6}{7} \cdot \frac{2}{7} = \frac{6 \cdot 2}{7 \cdot 7} = \frac{12}{49} \)
  18. \( \frac{45}{57} \cdot \frac{23}{19} = \frac{45 \cdot 23}{57 \cdot 19} = \frac{15 \cdot 23}{19 \cdot 19} = \frac{345}{361} \)
  19. \( \frac{20}{42} \cdot \frac{73}{73} = \frac{20}{42} \cdot 1 = \frac{10}{21} \)
  20. \( \frac{8}{16} \cdot \frac{13}{26} = \frac{1}{2} \cdot \frac{1}{2} = \frac{1}{4} \)

Ответ: \( \frac{1}{9}, \frac{3}{10}, \frac{6}{35}, \frac{5}{42}, \frac{2}{35}, \frac{1}{4}, \frac{3}{10}, \frac{12}{35}, \frac{5}{11}, \frac{3}{10}, \frac{2}{11}, 1, \frac{1}{7}, \frac{56}{45}, \frac{1}{10}, \frac{2}{21}, \frac{12}{49}, \frac{345}{361}, \frac{10}{21}, \frac{1}{4} \).