\[\boxed{\mathbf{30.}}\]
\[1)\ 20 + 10 = 30\]
\[20 - 10 = 10\]
\[40 + 10 = 50\]
\[40 - 10 = 30\]
\[70 + 10 = 80\]
\[70 - 10 = 60\]
\[50 + 10 = 60\]
\[50 - 10 = 40\]
\[90 + 10 = 100\]
\[90 - 10 = 80\]
\[30 + 10 = 40\]
\[30 - 10 = 20\]
\[60 + 10 = 70\]
\[60 - 10 = 50\]
\[80 + 10 = 90\]
\[80 - 10 = 70\]
\[10 + 10 = 20\]
\[10 - 10 = 0\]
\[2)\ 37 + 10 = 47\]
\[37 - 10 = 27\]
\[22 + 10 = 32\]
\[22 - 10 = 12\]
\[45 + 10 = 55\]
\[45 - 10 = 35\]
\[59 + 10 = 69\]
\[59 - 10 = 49\]
\[61 + 10 = 71\]
\[61 - 10 = 51\]
\[74 + 10 = 84\]
\[74 - 10 = 64\]
\[88 + 10 = 98\]
\[88 - 10 = 78\]
\[16 + 10 = 26\]
\[16 - 10 = 6\]