\[\boxed{\mathbf{16.}}\]
\[29 + 17 = 29 + 10 + 7 =\]
\[= 39 + 7 = 46\]
\[19 + 57 = 19 + 50 + 7 =\]
\[= 69 + 7 = 76\]
\[17 + 75 = 17 + 70 + 5 =\]
\[= 87 + 5 = 92\]
\[56 + 16 = 56 + 10 + 6 =\]
\[= 66 + 6 = 72\]
\[32 + 49 = 32 + 40 + 9 =\]
\[= 72 + 9 = 81\]
\[35 + 46 = 35 + 40 + 6 =\]
\[= 75 + 6 = 81\]
\[24 + 68 = 24 + 60 + 8 =\]
\[= 84 + 8 = 92\]
\[48 + 29 = 48 + 20 + 9 =\]
\[= 68 + 9 = 77\]
\[54 + 37 = 54 + 30 + 7 =\]
\[= 84 + 7 = 91\]