№ 3. Решите: 1) \(\frac{10}{15}\cdot\frac{3}{4}\); 2) \(\frac{11}{16}\cdot\frac{4}{55}\); 3) \(\frac{9}{10}\cdot\frac{5}{27}\); 4) \(\frac{13}{100}\cdot\frac{50}{13}\); 5) \(\frac{21}{32}\cdot\frac{64}{7}\).

1. \(\frac{10}{15}\cdot\frac{3}{4}=\frac{2}{3}\cdot\frac{3}{4}=\frac{1}{2}\).
2. \(\frac{11}{16}\cdot\frac{4}{55}=\frac{1}{4}\cdot\frac{1}{5}=\frac{1}{20}\).
3. \(\frac{9}{10}\cdot\frac{5}{27}=\frac{1}{3}\cdot\frac{1}{2}=\frac{1}{6}\).
4. \(\frac{13}{100}\cdot\frac{50}{13}=\frac{50}{100}=\frac{1}{2}\).
5. \(\frac{21}{32}\cdot\frac{64}{7}=3\cdot2=6\).

Ответ: 1) \(\frac{1}{2}\); 2) \(\frac{1}{20}\); 3) \(\frac{1}{6}\); 4) \(\frac{1}{2}\); 5) \(6\).