Question

а)4/5×10/11
б)3/7:9/20

Answer 1

$\frac{4}{5} \times \frac{10}{11} = \frac{8}{11}$

$\frac{3}{7} \div \frac{9}{20} = \frac{3}{7} \times \frac{20}{9} = \frac{20}{21}$

Answer 2

$\frac{4}{5} \times \frac{10}{11} = 4 \times \frac{2}{11} = \frac{8}{11} \\ \\ \frac{3}{7} \div \frac{9}{20} = \frac{3}{7} \times \frac{20}{9} = \frac{1}{7} \times \frac{20}{3} = \frac{20}{21}$

Удачи))))