Вычисли: а) 30/(5/12 + 1/4); б) (1 3/8 * 2)/11; в) (4 - 1 3/5)/(7 1/2 * 9/25); г) (8 1/3 : 2)/(1 9/10 + 4 7/20); д) ((7 1/3 : 1 1/6) : (8 : 7))/(9 : (1 3/11 + 2)); е) (3 4/7 : (6 1/28 - 3 3/4))/((1 5/6 * 1 5/22) : 18 * 5)

а) $\frac{30}{\frac{5}{12} + \frac{1}{4}} = \frac{30}{\frac{5+3}{12}} = \frac{30}{\frac{8}{12}} = \frac{30}{\frac{2}{3}} = 30 \cdot \frac{3}{2} = 45$ б) $\frac{1\frac{3}{8} \cdot 2}{11} = \frac{\frac{11}{8} \cdot 2}{11} = \frac{\frac{11}{4}}{11} = \frac{11}{4} \cdot \frac{1}{11} = \frac{1}{4} = 0,25$ в) $\frac{4 - 1\frac{3}{5}}{7\frac{1}{2} \cdot \frac{9}{25}} = \frac{2\frac{2}{5}}{\frac{15}{2} \cdot \frac{9}{25}} = \frac{\frac{12}{5}}{\frac{3 \cdot 9}{2 \cdot 5}} = \frac{\frac{12}{5}}{\frac{27}{10}} = \frac{12}{5} \cdot \frac{10}{27} = \frac{4 \cdot 2}{1 \cdot 9} = \frac{8}{9}$ г) $\frac{8\frac{1}{3} : 2}{1\frac{9}{10} + 4\frac{7}{20}} = \frac{\frac{25}{3} \cdot \frac{1}{2}}{1\frac{18}{20} + 4\frac{7}{20}} = \frac{\frac{25}{6}}{5\frac{25}{20}} = \frac{\frac{25}{6}}{6\frac{5}{20}} = \frac{\frac{25}{6}}{6\frac{1}{4}} = \frac{\frac{25}{6}}{\frac{25}{4}} = \frac{25}{6} \cdot \frac{4}{25} = \frac{4}{6} = \frac{2}{3}$ д) $\frac{(7\frac{1}{3} : 1\frac{1}{6}) : (8 : 7)}{9 : (1\frac{3}{11} + 2)} = \frac{(\frac{22}{3} \cdot \frac{6}{11}) : \frac{8}{7}}{9 : 3\frac{3}{11}} = \frac{(2 \cdot 2) : \frac{8}{7}}{9 : \frac{36}{11}} = \frac{4 \cdot \frac{7}{8}}{9 \cdot \frac{11}{36}} = \frac{\frac{7}{2}}{\frac{11}{4}} = \frac{7}{2} \cdot \frac{4}{11} = \frac{14}{11} = 1\frac{3}{11}$ е) $\frac{3\frac{4}{7} : (6\frac{1}{28} - 3\frac{3}{4})}{(1\frac{5}{6} \cdot 1\frac{5}{22}) : 18 \cdot 5} = \frac{\frac{25}{7} : (5\frac{29}{28} - 3\frac{21}{28})}{(\frac{11}{6} \cdot \frac{27}{22}) : 18 \cdot 5} = \frac{\frac{25}{7} : 2\frac{8}{28}}{(\frac{1 \cdot 9}{2 \cdot 2}) : 18 \cdot 5} = \frac{\frac{25}{7} : \frac{64}{28}}{\frac{9}{4} \cdot \frac{1}{18} \cdot 5} = \frac{\frac{25}{7} \cdot \frac{28}{64}}{\frac{1}{4 \cdot 2} \cdot 5} = \frac{\frac{25 \cdot 4}{64}}{\frac{5}{8}} = \frac{\frac{25}{16}}{\frac{5}{8}} = \frac{25}{16} \cdot \frac{8}{5} = \frac{5}{2} = 2,5$ **Ответ: а) 45; б) 0,25; в) 8/9; г) 2/3; д) 1 3/11; е) 2,5.**