\[\boxed{\mathbf{15.}}\]
\[35 + 5 = 40\]
\[33 + 7 = 40\]
\[39 + 1 = 40\]
\[34 + 6 = 40\]
\[62 + 8 = 70\]
\[64 + 6 = 70\]
\[67 + 3 = 70\]
\[65 + 5 = 70\]
\[94 + 6 = 100\]
\[98 + 2 = 100\]
\[93 + 7 = 100\]
\[96 + 4 = 100\]