\[\boxed{\mathbf{2}\mathbf{.}\mathbf{146}}\]
\[\textbf{а)}\ 35 + 56 + c = c + (35 + 56) =\]
\[= c + 91\]
\[\textbf{б)}\ 47 + k + 38 =\]
\[= k + (47 + 38) = k + 85\]
\[\textbf{в)}\ z + 64 + 17 =\]
\[= z + (64 + 17) = z + 81\]
\[\textbf{г)}\ 203 + p + 97 =\]
\[= p + (203 + 97) = p + 300\]