a) $$5 : \frac{2}{3} = \frac{5}{1} \cdot \frac{3}{2} = \frac{5 \cdot 3}{1 \cdot 2} = \frac{15}{2} = 7 \frac{1}{2}$$
Ответ: $$7 \frac{1}{2}$$
б) $$\frac{3}{8} : \frac{1}{3} = \frac{3}{8} \cdot \frac{3}{1} = \frac{3 \cdot 3}{8 \cdot 1} = \frac{9}{8} = 1 \frac{1}{8}$$
Ответ: $$1 \frac{1}{8}$$
в) $$\frac{1}{12} : \frac{5}{36} = \frac{1}{12} \cdot \frac{36}{5} = \frac{1 \cdot 36}{12 \cdot 5} = \frac{12 \cdot 3}{12 \cdot 5} = \frac{3}{5}$$
Ответ: $$\frac{3}{5}$$
г) $$\frac{14}{55} : \frac{5}{21} = \frac{14}{55} \cdot \frac{21}{5} = \frac{14 \cdot 21}{55 \cdot 5} = \frac{2 \cdot 7 \cdot 3 \cdot 7}{5 \cdot 11 \cdot 5} = \frac{294}{275} = 1 \frac{19}{275}$$
Ответ: $$1 \frac{19}{275}$$
д) $$\frac{121}{234} : \frac{11}{12} = \frac{121}{234} \cdot \frac{12}{11} = \frac{121 \cdot 12}{234 \cdot 11} = \frac{11 \cdot 11 \cdot 2 \cdot 6}{2 \cdot 117 \cdot 11} = \frac{11 \cdot 6}{117} = \frac{11 \cdot 2 \cdot 3}{3 \cdot 39} = \frac{11 \cdot 2}{39} = \frac{22}{39}$$
Ответ: $$\frac{22}{39}$$