\[\boxed{\mathbf{1056\ (1056)}\mathbf{.}\mathbf{\ }\mathbf{Еуроки}\mathbf{\ - \ }\mathbf{ДЗ}\mathbf{\ }\mathbf{без}\mathbf{\ }\mathbf{мороки}}\]
\[\textbf{а)} - 5 \bullet ( - 0,8) = + (5 \bullet 0,8) = 5 \bullet \frac{8}{10} = \frac{8}{2} = 4\]
\[8 \bullet 0,5 = 8 \bullet \frac{1}{2} = 4\]
\[Значит,\ - 5 \bullet ( - 0,8) = 8 \bullet 0,5.\]
\[\textbf{б)}\frac{1}{5} - \frac{1}{4} = \frac{4}{20} - \frac{5}{20} = \frac{4 - 5}{20} = \frac{- 1}{20} = - \frac{1}{20} = - 0,05\]
\[\frac{1}{5}\ :\left( - \frac{1}{4} \right) = \frac{1}{5} \bullet \left( - \frac{4}{1} \right) = - \frac{4}{5} = - 0,8\]
\[Значит,\ \ \ \frac{1}{5} - \frac{1}{4} > \frac{1}{5}\ :\left( - \frac{1}{4} \right).\]