Реши примеры: 1.78 а) 4/9 * 63/64 * 2/7; 1.78 б) (1/2)^2 : 5/6; 1.78 в) (1 - 1/3) : (1/3 - 1/4); 1.79 а) (7/30 + 1/2 + 4/15) : (49/50 - 14/25 - 2/5); 1.79 б) 39 : (3/8 + 1/6) + (3/10)^2 * (2/3 - 7/18).

Задание 1.78 а) $\frac{4}{9} \cdot \frac{63}{64} \cdot \frac{2}{7} = \frac{4 \cdot 63 \cdot 2}{9 \cdot 64 \cdot 7} = \frac{1 \cdot 7 \cdot 1}{1 \cdot 8 \cdot 1} = \frac{7}{8}$ б) $(\frac{1}{2})^2 : \frac{5}{6} = \frac{1}{4} : \frac{5}{6} = \frac{1}{4} \cdot \frac{6}{5} = \frac{1 \cdot 3}{2 \cdot 5} = \frac{3}{10}$ в) $(1 - \frac{1}{3}) : (\frac{1}{3} - \frac{1}{4}) = (\frac{3}{3} - \frac{1}{3}) : (\frac{4}{12} - \frac{3}{12}) = \frac{2}{3} : \frac{1}{12} = \frac{2}{3} \cdot \frac{12}{1} = \frac{2 \cdot 4}{1 \cdot 1} = 8$ Задание 1.79 а) $(\frac{7}{30} + \frac{1}{2} + \frac{4}{15}) : (\frac{49}{50} - \frac{14}{25} - \frac{2}{5}) = (\frac{7}{30} + \frac{15}{30} + \frac{8}{30}) : (\frac{49}{50} - \frac{28}{50} - \frac{20}{50}) = \frac{30}{30} : \frac{1}{50} = 1 : \frac{1}{50} = 1 \cdot \frac{50}{1} = 50$ б) $39 : (\frac{3}{8} + \frac{1}{6}) + (\frac{3}{10})^2 \cdot (\frac{2}{3} - \frac{7}{18}) = 39 : (\frac{9}{24} + \frac{4}{24}) + \frac{9}{100} \cdot (\frac{12}{18} - \frac{7}{18}) = 39 : \frac{13}{24} + \frac{9}{100} \cdot \frac{5}{18} = 39 \cdot \frac{24}{13} + \frac{1 \cdot 1}{20 \cdot 2} = 3 \cdot 24 + \frac{1}{40} = 72 + \frac{1}{40} = 72\frac{1}{40}$ **Ответ:** 1. 78: а) $\frac{7}{8}$ б) $\frac{3}{10}$ в) $8$ 1. 79: а) $50$ б) $72\frac{1}{40}$