\[\boxed{\mathbf{228.}}\]
\[\textbf{а)}\ C_{8}^{2} = \frac{8!}{2!6!} = \frac{7 \cdot 8}{2} = 28.\]
\[\textbf{б)}\ C_{8}^{6} = C_{8}^{2} = 28.\]
\[\textbf{в)}\ C_{8}^{5} = \frac{8!}{5!3!} = \frac{6 \cdot 7 \cdot 8}{2 \cdot 3} = 56.\]
\[\textbf{г)}\ C_{8}^{3} = C_{8}^{5} = 56.\]