\[0,8 = \frac{4}{5} = \frac{52}{70}\]
\[\frac{4}{7} = \frac{40}{70}\]
\[0,9 = \frac{9}{10} = \frac{63}{70}\]
\[\frac{3}{7} = \frac{30}{70}\]
\[0,5 = \frac{1}{2} = \frac{35}{70}\]
\[Числа\ в\ порядке\ убывания:\]
\[0,9;\ \ 0,8;\ \ \ \frac{4}{7};\ \ 0,5;\ \ \ \frac{3}{7}.\]