\[\boxed{\mathbf{Проверочная\ работа\ №}\mathbf{3}\mathbf{.}}\]
\[\boxed{\mathbf{1}\mathbf{.}}\]
\[50 - (m + 15)\]
\[\boxed{\mathbf{2}\mathbf{.}}\]
\[(36 + x) - 20\]
\[\boxed{\mathbf{3}\mathbf{.}}\]
\[28 + (n + 40)\]
\[\boxed{\mathbf{4}\mathbf{.}}\]
\[60 + x + 50\]
\[\boxed{\mathbf{5}\mathbf{.}}\]
\[70 - (30 + x)\]
\[\boxed{\mathbf{6}\mathbf{.}}\]
\[\mathbf{Да.}\]
\[\boxed{\mathbf{7}\mathbf{.}}\]
\[\mathbf{Нет,\ она\ является\ слагаемым.}\]
\[\boxed{\mathbf{8}\mathbf{.}}\]
\[\mathbf{Да.}\]