Ответ:
Решение:
- \(12 : 3 \frac{3}{8} - 1 \frac{1}{4} : 1 \frac{15}{32} = 12 : \frac{27}{8} - \frac{5}{4} : \frac{47}{32} = 12 \cdot \frac{8}{27} - \frac{5}{4} \cdot \frac{32}{47} = \frac{96}{27} - \frac{160}{188} = \frac{32}{9} - \frac{40}{47} = \frac{32 \cdot 47 - 40 \cdot 9}{9 \cdot 47} = \frac{1504 - 360}{423} = \frac{1144}{423} \approx 2.70\)
- \(1 \frac{31}{35} : \left( 2 - \frac{8}{9} : 1 \frac{19}{45} \right) = \frac{66}{35} : \left( 2 - \frac{8}{9} : \frac{64}{45} \right) = \frac{66}{35} : \left( 2 - \frac{8}{9} \cdot \frac{45}{64} \right) = \frac{66}{35} : \left( 2 - \frac{8 \cdot 45}{9 \cdot 64} \right) = \frac{66}{35} : \left( 2 - \frac{5}{8} \right) = \frac{66}{35} : \left( \frac{16 - 5}{8} \right) = \frac{66}{35} : \frac{11}{8} = \frac{66}{35} \cdot \frac{8}{11} = \frac{6 \cdot 8}{35} = \frac{48}{35} = 1 \frac{13}{35}\)
- \(\left( 1 \frac{1}{35} : \frac{4}{5} - 1 \frac{8}{35} \right) \cdot 3 \frac{1}{3} = \left( \frac{36}{35} : \frac{4}{5} - \frac{43}{35} \right) \cdot \frac{10}{3} = \left( \frac{36}{35} \cdot \frac{5}{4} - \frac{43}{35} \right) \cdot \frac{10}{3} = \left( \frac{9}{7} - \frac{43}{35} \right) \cdot \frac{10}{3} = \left( \frac{45 - 43}{35} \right) \cdot \frac{10}{3} = \frac{2}{35} \cdot \frac{10}{3} = \frac{20}{105} = \frac{4}{21}\)
- \(\left( 7 - 1 \frac{5}{9} : \frac{5}{24} \right) \cdot \frac{20}{27} = \left( 7 - \frac{14}{9} : \frac{5}{24} \right) \cdot \frac{20}{27} = \left( 7 - \frac{14}{9} \cdot \frac{24}{5} \right) \cdot \frac{20}{27} = \left( 7 - \frac{14 \cdot 8}{3 \cdot 5} \right) \cdot \frac{20}{27} = \left( 7 - \frac{112}{15} \right) \cdot \frac{20}{27} = \left( \frac{105 - 112}{15} \right) \cdot \frac{20}{27} = -\frac{7}{15} \cdot \frac{20}{27} = -\frac{7 \cdot 4}{3 \cdot 27} = -\frac{28}{81}\)
Ответ: 1) \(\frac{1144}{423}\) 2) \(1 \frac{13}{35}\) 3) \(\frac{4}{21}\) 4) \(-\frac{28}{81}\)
