1. Выполните умножение: а) 1) 2/9 · 3/4; 2) 15/14 · 7/5; 3) 28/45 · 5/21; 4) 8/15 · 25/28; б) 1) 7/64 · 16/35; 2) 4/45 · 9/56; 3) 1/7 · 42/53; 4) 14/15 · 5/7.

Используем правило умножения дробей: \(\frac{a}{b}\cdot\frac{c}{d}=\frac{ac}{bd}\).

1. а) \(\frac{2}{9}\cdot\frac{3}{4}=\frac{6}{36}=\frac{1}{6}\); \(\frac{15}{14}\cdot\frac{7}{5}=\frac{3}{2}=1\frac{1}{2}\); \(\frac{28}{45}\cdot\frac{5}{21}=\frac{4}{27}\); \(\frac{8}{15}\cdot\frac{25}{28}=\frac{10}{21}\).
2. б) \(\frac{7}{64}\cdot\frac{16}{35}=\frac{1}{20}\); \(\frac{4}{45}\cdot\frac{9}{56}=\frac{1}{70}\); \(\frac{1}{7}\cdot\frac{42}{53}=\frac{6}{53}\); \(\frac{14}{15}\cdot\frac{5}{7}=\frac{2}{3}\).

Ответ: а) 1) \(\frac{1}{6}\); 2) \(1\frac{1}{2}\); 3) \(\frac{4}{27}\); 4) \(\frac{10}{21}\); б) 1) \(\frac{1}{20}\); 2) \(\frac{1}{70}\); 3) \(\frac{6}{53}\); 4) \(\frac{2}{3}\).