\[\boxed{\mathbf{9}\mathbf{.}}\]
\[\textbf{а)}\ 25 + 7 = 32\]
\[25 - 7 = 18\]
\[36 + 10 + 7 = 46 + 7 = 53\]
\[36 - 10 - 7 = 26 - 7 = 19\]
\[\textbf{б)}\ 62 - 33 - 15 = 29 - 15 = 14\]
\[62 - (33 - 15) = 62 - 18 = 44\]