\[\boxed{\mathbf{1.}}\]
\[9 + 5 = 9 + 1 + 4 = 10 + 4 = 14\]
\[8 + 4 = 8 + 2 + 2 = 10 + 2 = 12\]
\[7 + 7 = 7 + 3 + 4 = 10 + 4 = 14\]
\[6 + 7 = 6 + 4 + 3 = 10 + 3 = 13\]
\[4 + 9 = 4 + 6 + 3 = 10 + 3 = 13\]
\[3 + 8 = 3 + 7 + 1 = 10 + 1 = 11\]
\[7 + 9 = 7 + 3 + 6 = 10 + 6 = 16\]
\[9 + 8 = 9 + 1 + 7 = 10 + 7 = 17\]
\[9 + 9 = 9 + 1 + 8 = 10 + 8 = 18\]