Вопрос:

1. Выполните умножение: а) \(\frac{7}{30}\cdot\frac{6}{21}\); б) \(\frac{4}{12}\cdot\frac{18}{20}\); в) \(\frac{21}{25}\cdot\frac{15}{42}\); г) \(\frac{14}{24}\cdot\frac{16}{21}\); д) \(\frac{50}{70}\cdot\frac{77}{150}\); е) \(\frac{23}{45}\cdot\frac{9}{46}\); ж) \(\frac{30}{66}\cdot\frac{7}{90}\); з) \(\frac{26}{32}\cdot\frac{12}{13}\).

Ответ:

Сократим дроби и перемножим числители и знаменатели:

  1. \(\frac{7}{30}\cdot\frac{6}{21}=\frac{1}{5}\cdot\frac{2}{7}=\frac{2}{35}\).
  2. \(\frac{4}{12}\cdot\frac{18}{20}=\frac{1}{3}\cdot\frac{9}{10}=\frac{3}{10}\).
  3. \(\frac{21}{25}\cdot\frac{15}{42}=\frac{1}{2}\cdot\frac{3}{5}=\frac{3}{10}\).
  4. \(\frac{14}{24}\cdot\frac{16}{21}=\frac{7}{12}\cdot\frac{16}{21}=\frac{2}{9}\).
  5. \(\frac{50}{70}\cdot\frac{77}{150}=\frac{5}{7}\cdot\frac{11}{30}=\frac{11}{42}\).
  6. \(\frac{23}{45}\cdot\frac{9}{46}=\frac{1}{5}\cdot\frac{1}{2}=\frac{1}{10}\).
  7. \(\frac{30}{66}\cdot\frac{7}{90}=\frac{5}{11}\cdot\frac{7}{90}=\frac{7}{198}\).
  8. \(\frac{26}{32}\cdot\frac{12}{13}=\frac{13}{16}\cdot\frac{12}{13}=\frac{3}{4}\).

Ответ: а) \(\frac{2}{35}\); б) \(\frac{3}{10}\); в) \(\frac{3}{10}\); г) \(\frac{2}{9}\); д) \(\frac{11}{42}\); е) \(\frac{1}{10}\); ж) \(\frac{7}{198}\); з) \(\frac{3}{4}\).