\[\boxed{\mathbf{25.}}\]
\[32 - 17 = 32 - 10 - 7 =\]
\[= 22 - 7 = 15\]
\[41 - 25 = 41 - 20 - 5 =\]
\[= 21 - 5 = 16\]
\[53 - 26 = 53 - 20 - 6 =\]
\[= 33 - 6 = 27\]
\[55 - 49 = 55 - 40 - 9 =\]
\[= 15 - 9 = 6\]
\[86 - 68 = 86 - 60 - 8 =\]
\[= 26 - 8 = 18\]
\[65 - 46 = 65 - 40 - 6 =\]
\[= 25 - 6 = 19\]
\[73 - 18 = 73 - 10 - 8 =\]
\[= 63 - 8 = 55\]
\[82 - 39 = 82 - 30 - 9 =\]
\[= 52 - 9 = 43\]
\[94 - 57 = 94 - 50 - 7 =\]
\[= 44 - 7 = 37\]
\[61 - 53 = 61 - 50 - 3 =\]
\[= 11 - 3 = 8\]