\[\boxed{\mathbf{17.}}\]
\[\textbf{а)}\ 12 + 0 = 12\]
\[32 + 0 = 32\]
\[5 - 0 = 5\]
\[45 - 0 = 45\]
\[\textbf{б)}\ 26 + 1 + 0 = 27\]
\[37 - 1 - 0 = 36\]
\[63 + 10 + 0 = 73\]
\[85 - 10 - 0 = 75\]