4 8 20 / 5 10 2 =

\( \frac{4}{5} : \frac{8}{10} : \frac{20}{2} = \frac{4}{5} \times \frac{10}{8} \times \frac{2}{20} = \frac{4 \times 10 \times 2}{5 \times 8 \times 20} = \frac{80}{800} = \frac{1}{10} \)

Ответ: \( \frac{1}{10} \)