§ Задание 12
\[\boxed{\mathbf{12.}}\]
\[30 + 20 = 50\]
\[50 + 30 = 80\]
\[20 + 40 = 60\]
\[60 + 30 = 90\]
\[30 + 40 = 70\]
\[60 + 20 = 80\]
\[50 + 50 = 100\]
\[60 + 40 = 100\]
\[\boxed{\mathbf{12.}}\]
\[30 + 20 = 50\]
\[50 + 30 = 80\]
\[20 + 40 = 60\]
\[60 + 30 = 90\]
\[30 + 40 = 70\]
\[60 + 20 = 80\]
\[50 + 50 = 100\]
\[60 + 40 = 100\]