2. Действия с обыкновенными дробями. A) 5/12 * (1/5 + 3/25); Б) 9/14 * (17/24 - 5/12); В) 14/25 : 7/45 - 3; Г) 2 - 15/28 : 10/21 Д) 1 - 4/9 : 16/27

A) $$\frac{5}{12} * (\frac{1}{5} + \frac{3}{25}) = \frac{5}{12} * (\frac{5}{25} + \frac{3}{25}) = \frac{5}{12} * \frac{8}{25} = \frac{40}{300} = \frac{2}{15}$$ Б) $$\frac{9}{14} * (\frac{17}{24} - \frac{5}{12}) = \frac{9}{14} * (\frac{17}{24} - \frac{10}{24}) = \frac{9}{14} * \frac{7}{24} = \frac{63}{336} = \frac{9}{48} = \frac{3}{16}$$ В) $$\frac{14}{25} : \frac{7}{45} - 3 = \frac{14}{25} * \frac{45}{7} - 3 = \frac{2}{5} * \frac{9}{1} - 3 = \frac{18}{5} - 3 = \frac{18}{5} - \frac{15}{5} = \frac{3}{5}$$ Г) $$2 - \frac{15}{28} : \frac{10}{21} = 2 - \frac{15}{28} * \frac{21}{10} = 2 - \frac{3}{4} * \frac{3}{2} = 2 - \frac{9}{8} = \frac{16}{8} - \frac{9}{8} = \frac{7}{8}$$ Д) $$1 - \frac{4}{9} : \frac{16}{27} = 1 - \frac{4}{9} * \frac{27}{16} = 1 - \frac{1}{1} * \frac{3}{4} = 1 - \frac{3}{4} = \frac{4}{4} - \frac{3}{4} = \frac{1}{4}$$