Выполните деление:
а) $\frac{4}{9} : 2$;
б) $\frac{5}{7} : 3$;
в) $\frac{10}{21} : 5$;
г) $\frac{2}{3} : 4$;
д) $\frac{9}{10} : 3$.
$\frac{4}{9} : 2 = \frac{4}{9} * \frac{1}{2} = \frac{2}{9} * \frac{1}{1} = \frac{2}{9}$
$\frac{5}{7} : 3 = \frac{5}{7} * \frac{1}{3} = \frac{5}{21}$
$\frac{10}{21} : 5 = \frac{10}{21} * \frac{1}{5} = \frac{2}{21} * \frac{1}{1} = \frac{2}{21}$
$\frac{2}{3} : 4 = \frac{2}{3} * \frac{1}{4} = \frac{1}{3} * \frac{1}{2} = \frac{1}{6}$
$\frac{9}{10} : 3 = \frac{9}{10} * \frac{1}{3} = \frac{3}{10} * \frac{1}{1} = \frac{3}{10}$