Ответ:
- \(\frac{4}{7}\cdot21=4\cdot3=12\).
- \(36\cdot\frac{3}{24}=36\cdot\frac{1}{8}=\frac{36}{8}=\frac{9}{2}=4\frac{1}{2}\).
- \(\frac{8}{14}\cdot\frac{2}{3}=\frac{4}{7}\cdot\frac{2}{3}=\frac{8}{21}\).
- \(\frac{21}{8}\cdot\frac{5}{7}=\frac{3\cdot5}{8}=\frac{15}{8}=1\frac{7}{8}\).
Ответ: 1) 12; 2) \(4\frac{1}{2}\); 3) \(\frac{8}{21}\); 4) \(1\frac{7}{8}\).
