§ Задание 1
\[\boxed{\mathbf{1}\mathbf{.}}\]
\[\mathbf{Слева\ 4\ десятка,\ справа\ }\]
\[\mathbf{3\ десятка.}\]
\[40 + 30 = 70\]
\[30 + 40 = 70\]
\[70 - 40 = 30\]
\[70 - 30 = 40\]
\[\boxed{\mathbf{1}\mathbf{.}}\]
\[\mathbf{Слева\ 4\ десятка,\ справа\ }\]
\[\mathbf{3\ десятка.}\]
\[40 + 30 = 70\]
\[30 + 40 = 70\]
\[70 - 40 = 30\]
\[70 - 30 = 40\]