Ответ:
- \(\frac{7}{8}\cdot\frac{16}{21}=\frac{2}{3}\).
- \(1\frac{8}{25}\cdot1\frac{4}{11}=\frac{33}{25}\cdot\frac{15}{11}=\frac{9}{5}=1\frac{4}{5}\).
- \(1\frac{5}{7}\cdot1\frac{17}{18}=\frac{12}{7}\cdot\frac{35}{18}=\frac{10}{3}=3\frac{1}{3}\).
- \(5\cdot3\frac{7}{15}=5\cdot\frac{52}{15}=\frac{52}{3}=17\frac{1}{3}\).
Ответ: а) \(\frac{2}{3}\); б) \(1\frac{4}{5}\); в) \(3\frac{1}{3}\); г) \(17\frac{1}{3}\).
