Для деления дробей необходимо первую дробь умножить на дробь, обратную второй.
a) $$\frac{5}{9} : \frac{3}{4} = \frac{5}{9} \cdot \frac{4}{3} = \frac{5 \cdot 4}{9 \cdot 3} = \frac{20}{27}$$
б) $$\frac{1}{6} : \frac{2}{5} = \frac{1}{6} \cdot \frac{5}{2} = \frac{1 \cdot 5}{6 \cdot 2} = \frac{5}{12}$$
в) $$\frac{7}{12} : \frac{1}{5} = \frac{7}{12} \cdot \frac{5}{1} = \frac{7 \cdot 5}{12 \cdot 1} = \frac{35}{12}$$
г) $$\frac{3}{11} : \frac{6}{7} = \frac{3}{11} \cdot \frac{7}{6} = \frac{3 \cdot 7}{11 \cdot 6} = \frac{21}{66} = \frac{7}{22}$$
a) $$\frac{1}{9} : \frac{2}{3} = \frac{1}{9} \cdot \frac{3}{2} = \frac{1 \cdot 3}{9 \cdot 2} = \frac{3}{18} = \frac{1}{6}$$
б) $$\frac{4}{7} : \frac{12}{5} = \frac{4}{7} \cdot \frac{5}{12} = \frac{4 \cdot 5}{7 \cdot 12} = \frac{20}{84} = \frac{5}{21}$$
в) $$\frac{9}{16} : \frac{3}{4} = \frac{9}{16} \cdot \frac{4}{3} = \frac{9 \cdot 4}{16 \cdot 3} = \frac{36}{48} = \frac{3}{4}$$
г) $$\frac{10}{21} : \frac{14}{15} = \frac{10}{21} \cdot \frac{15}{14} = \frac{10 \cdot 15}{21 \cdot 14} = \frac{150}{294} = \frac{25}{49}$$
a) $$\frac{1}{8} : \frac{1}{4} = \frac{1}{8} \cdot \frac{4}{1} = \frac{1 \cdot 4}{8 \cdot 1} = \frac{4}{8} = \frac{1}{2}$$
б) $$\frac{1}{5} : \frac{1}{25} = \frac{1}{5} \cdot \frac{25}{1} = \frac{1 \cdot 25}{5 \cdot 1} = \frac{25}{5} = 5$$
в) $$\frac{3}{10} : \frac{1}{100} = \frac{3}{10} \cdot \frac{100}{1} = \frac{3 \cdot 100}{10 \cdot 1} = \frac{300}{10} = 30$$
г) $$\frac{1}{15} : \frac{1}{15} = \frac{1}{15} \cdot \frac{15}{1} = \frac{1 \cdot 15}{15 \cdot 1} = \frac{15}{15} = 1$$