Вычислите По Действиям: в) (2/5 - 2/7) : 2/7 * 2/5 = г) (5/6 - 3/10) : (3/10 + 2/15) =

$\frac{2}{5} - \frac{2}{7}= \frac{14}{35}- \frac{10}{35}= \frac{4}{35}$
$\frac{4}{35}: \frac{2}{7}= \frac{4}{35}* \frac{7}{2}= \frac{2}{5}$
$\frac{2}{5}* \frac{2}{5}= \frac{4}{25}$
$\frac{5}{6}- \frac{3}{10}= \frac{50}{60}- \frac{18}{60}= \frac{32}{60}= \frac{8}{15}$
$\frac{3}{10} + \frac{2}{15}= \frac{9}{30}+ \frac{4}{30}= \frac{13}{30}$
$\frac{8}{15}: \frac{13}{30}= \frac{8}{15}* \frac{30}{13} =\frac{16}{13}=1 \frac{3}{13}$