\[\boxed{\text{4.\ 349}}\]
\[\textbf{а)} - 2\ :8 = - \frac{2}{8} = - \frac{1}{4}\]
\[- 2 - 11 = - 13\]
\[- 2 \cdot \frac{4}{3} = - \frac{8}{3} = - 2\frac{2}{3}\]
\[- 2 + \frac{2}{5} = - 1\frac{3}{5}\]
\[- 2 + 4,6 = 2,6\]
\[- 2\ :\frac{4}{7} = - 2 \cdot \frac{7}{4} = - \frac{7}{2} = - 3,5\]
\[- 2 - \frac{5}{8} = - 2\frac{5}{8}\]
\[- 2 \cdot \frac{1}{4} = - \frac{1}{2}\]
\[\textbf{б)} - \frac{5}{8} \cdot 8 = - 5\]
\[- \frac{5}{8} \cdot 0 = 0\]
\[- \frac{5}{8} + 5 = 4\frac{3}{8}\]
\[- \frac{5}{8}\ :\frac{1}{8} = - \frac{5}{8} \cdot 8 = - 5\]
\[- \frac{5}{8} - \frac{1}{4} = - \frac{5}{8} - \frac{2}{8} = - \frac{7}{8}\]
\[- \frac{5}{8} + \frac{2}{3} = - \frac{15}{24} + \frac{16}{24} = \frac{1}{24}\]
\[- \frac{5}{8} \cdot ( - 8) = \frac{5}{8} \cdot 8 = 5\]