\[\boxed{\mathbf{334\ (334).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ \frac{9}{35} \cdot 8 = \frac{9 \cdot 8}{35} = \frac{72}{35} = 2\frac{2}{35}\]
\[2)\ \frac{7}{24} \cdot 16 = \frac{7 \cdot 16}{24} =\]
\[= \frac{7 \cdot 2}{3} = \frac{14}{3} = 4\frac{2}{3}\]
\[3)\ 42 \cdot \frac{4}{7} = \frac{42 \cdot 4}{7} = 6 \cdot 4 = 24\]
\[4)\ \frac{6}{19} \cdot 57 = \frac{6 \cdot 57}{19} = 6 \cdot 3 = 18\]