\[\boxed{\mathbf{2.2}\mathbf{70}}\]
Пояснение.
Решение.
\[\textbf{а)}\ \frac{3}{7} \cdot \frac{2}{3} = \frac{3 \cdot 2}{7 \cdot 3} = \frac{2}{7}\]
\[\textbf{б)}\ \frac{7}{10} \cdot \frac{4}{15} = \frac{7 \cdot 4}{10 \cdot 15} = \frac{7 \cdot 2}{5 \cdot 15} =\]
\[= \frac{14}{75}\]
\[\textbf{в)}\ \frac{15}{16} \cdot \frac{10}{11} = \frac{15 \cdot 10}{16 \cdot 11} = \frac{15 \cdot 5}{8 \cdot 11} =\]
\[= \frac{75}{88}\]
\[\textbf{г)}\ \frac{38}{45} \cdot \frac{18}{19} = \frac{38 \cdot 18}{45 \cdot 19} = \frac{2 \cdot 2}{5 \cdot 1} = \frac{4}{5}\]
\[\textbf{д)}\ \frac{12}{25} \cdot \frac{5}{16} = \frac{12 \cdot 5}{25 \cdot 16} = \frac{3 \cdot 1}{5 \cdot 4} =\]
\[= \frac{3}{20}\]
\[\textbf{е)}\ \frac{9}{26} \cdot \frac{13}{18} = \frac{9 \cdot 13}{26 \cdot 18} = \frac{1 \cdot 1}{2 \cdot 2} = \frac{1}{4}\]