\[\boxed{\mathbf{329\ (329).}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[1)\ 12 \cdot 3a = 36a\]
\[2)\ 0,6a \cdot 7b = 4,2ab\]
\[3)\ 0,8m \cdot 0,5n \cdot 4p =\]
\[= 0,4mn \cdot 4p = 1,6mnp\]
\[\boxed{\mathbf{329}\mathbf{.}}\]
\[1)\ \frac{3}{8} = \frac{9}{24}\]
\[2)\ \frac{1}{5} = \frac{6}{30}\]
\[3)\ \frac{4}{19} = \frac{20}{95}\]
\[4)\ \frac{8}{45} = \frac{32}{180}\]