\[\boxed{\mathbf{Страница}\mathbf{\ 67.}\mathbf{\ }\mathbf{Еуроки\ - \ ДЗ\ без\ мороки}}\]
\[\boxed{\mathbf{38.}}\]
\[72\ :8 + 57 = 66\]
\[54\ :9 \cdot 12 = 72\]
\[70 \cdot 8 + 40 = 600\]
\[780\ :6\ :5 = 26\]
\[\boxed{\mathbf{39.}}\]
\[\boxed{\mathbf{40.}}\]
\[1)\ 240 \cdot 5 = 1200\ (г) - вес\ всех\ \]
\[пряников.\]
\[2)\ 1200\ :8 = 150\ (грамм) -\]
\[масса\ одной\ пачки\ печенья.\]
\[Ответ:150\ грамм.\]
\[\boxed{\mathbf{41.}}\]
\[15\overset{\cdot 6}{\overbrace{\Longrightarrow}}90\overset{:\ 9}{\overbrace{\Longrightarrow}}10\overset{\cdot 11}{\overbrace{\Longrightarrow}}110\overset{+ 90}{\overbrace{\Longrightarrow}}200\overset{:\ 5}{\overbrace{\Longrightarrow}}\]
\[\overset{:\ 5}{\overbrace{\Longrightarrow}}40\overset{\cdot 8}{\overbrace{\Longrightarrow}}320.\]