\[\boxed{\text{4.\ 355}}\]
\[\textbf{а)} - 40\ :( - 4) = 10\]
\[\textbf{б)}\ 7\ :( - 50) = - \frac{7}{50} = - \frac{14}{100} =\]
\[= - 0,14\]
\[\textbf{в)} - 4\ :9 = - \frac{4}{9}\]
\[\textbf{г)}\ 4,2\ :( - 7) = - 0,6\]
\[\textbf{д)} - 4,8\ :2,4 = - 2\]
\[\textbf{е)} - 7,2\ :( - 0,04) = 720\ :4 =\]
\[= 180\]
\[\textbf{ж)} - \frac{7}{11}\ :\frac{7}{11} = - 1\]
\[\textbf{з)} - 4\frac{2}{9}\ :\left( - 6\frac{1}{3} \right) = \frac{38}{9}\ :\frac{19}{3} =\]
\[= \frac{38}{9} \cdot \frac{3}{19} = \frac{2}{3}\]
\[\textbf{и)} - \frac{4}{5}\ :1\frac{3}{5} = - \frac{4}{5}\ :\frac{8}{5} = - \frac{4}{5} \cdot \frac{5}{8} =\]
\[= - \frac{1}{2} = - 0,5\]