\[\boxed{\mathbf{233.}}\]
\[\textbf{а)}\ C_{n}^{2} + C_{n}^{3}.\]
\[\textbf{б)}\ Не\ более\ 5\ успехов:\]
\[0,\ 1,\ 2,\ 3,\ 4,\ 5.\]
\[C_{n}^{0} + C_{n}^{1} + C_{n}^{2} + C_{n}^{3} + C_{n}^{4} + C_{n}^{5} =\]
\[= 1 + n + C_{n}^{2} + C_{n}^{3} + C_{n}^{4} + C_{n}^{5}.\]
\[\textbf{в)}\ C_{n}^{4} + C_{n}^{6} + C_{n}^{9}.\]
\[\textbf{г)}\ Менее\ 4:0,\ 1,\ 2,\ 3.\]
\[C_{n}^{0} + C_{n}^{1} + C_{n}^{2} + C_{n}^{3} =\]
\[= 1 + n + C_{n}^{2} + C_{n}^{3}.\]