§ Задание 7
\[\boxed{\mathbf{7.}}\]
\[60 - 4 = 56\]
\[60 - 40 = 20\]
\[70 - 3 = 67\]
\[70 - 30 = 40\]
\[80 - 2 = 78\]
\[80 - 20 = 60\]
\[90 - 9 = 81\]
\[90 - 90 = 0\]
\[\boxed{\mathbf{7.}}\]
\[60 - 4 = 56\]
\[60 - 40 = 20\]
\[70 - 3 = 67\]
\[70 - 30 = 40\]
\[80 - 2 = 78\]
\[80 - 20 = 60\]
\[90 - 9 = 81\]
\[90 - 90 = 0\]