Объясни, как решить математические выражения с дробями под номерами 1-8

Конечно, сейчас помогу! 1) $2\frac{1}{3} : (\frac{5}{8} - \frac{8}{3}) - 2 \cdot 1\frac{3}{7} = \frac{7}{3} : (\frac{15-64}{24}) - 2 \cdot \frac{10}{7} = \frac{7}{3} : (-\frac{49}{24}) - \frac{20}{7} = \frac{7}{3} \cdot (-\frac{24}{49}) - \frac{20}{7} = -\frac{8}{7} - \frac{20}{7} = -\frac{28}{7} = -4$ 2) $(7 - 1\frac{5}{9} : \frac{7}{24}) : \frac{20}{27} = (7 - \frac{14}{9} : \frac{7}{24}) : \frac{20}{27} = (7 - \frac{14}{9} \cdot \frac{24}{7}) : \frac{20}{27} = (7 - \frac{2}{3} \cdot \frac{8}{1}) : \frac{20}{27} = (7 - \frac{16}{3}) : \frac{20}{27} = (\frac{21-16}{3}) : \frac{20}{27} = \frac{5}{3} : \frac{20}{27} = \frac{5}{3} \cdot \frac{27}{20} = \frac{1}{1} \cdot \frac{9}{4} = \frac{9}{4} = 2\frac{1}{4}$ 3) $1\frac{31}{35} : (2 - \frac{8}{9} : 1\frac{19}{45}) = \frac{66}{35} : (2 - \frac{8}{9} : \frac{64}{45}) = \frac{66}{35} : (2 - \frac{8}{9} \cdot \frac{45}{64}) = \frac{66}{35} : (2 - \frac{1}{1} \cdot \frac{5}{8}) = \frac{66}{35} : (2 - \frac{5}{8}) = \frac{66}{35} : (\frac{16-5}{8}) = \frac{66}{35} : \frac{11}{8} = \frac{66}{35} \cdot \frac{8}{11} = \frac{6}{35} \cdot \frac{8}{1} = \frac{48}{35} = 1\frac{13}{35}$ 4) $(5\frac{1}{16} - 1\frac{1}{8}) (\frac{5}{6} + \frac{3}{14}) = (\frac{81}{16} - \frac{9}{8}) (\frac{35+9}{42}) = (\frac{81-18}{16}) (\frac{44}{42}) = \frac{63}{16} \cdot \frac{22}{21} = \frac{3}{8} \cdot \frac{11}{1} = \frac{33}{8} = 4\frac{1}{8}$ 5) $(2\frac{13}{48} + 2\frac{5}{12}) : 3\frac{3}{4} - 9\frac{3}{4} : 12 = (2\frac{13}{48} + 2\frac{20}{48}) : \frac{15}{4} - \frac{39}{4} : 12 = \frac{109}{24} : \frac{15}{4} - \frac{13}{4} : 4 = \frac{109}{24} \cdot \frac{4}{15} - \frac{13}{4} \cdot \frac{1}{4} = \frac{109}{6} \cdot \frac{1}{15} - \frac{13}{16} = \frac{109}{90} - \frac{13}{16} = \frac{872 - 1170}{720} = -\frac{298}{720} = -\frac{149}{360}$ 6) $4\frac{1}{3} \cdot 5 + 2,4 : (-0,1) - \frac{14}{15} : 1\frac{2}{5} = \frac{13}{3} \cdot 5 + 2,4 : (-0,1) - \frac{14}{15} : \frac{7}{5} = \frac{65}{3} - 24 - \frac{14}{15} \cdot \frac{5}{7} = \frac{65}{3} - 24 - \frac{2}{3} = \frac{63}{3} - 24 = 21 - 24 = -3$ 7) $3\frac{1}{7} \cdot (-4) - 1,8 : (-0,1) + \frac{20}{21} : 1\frac{1}{3} = \frac{22}{7} \cdot (-4) - 1,8 : (-0,1) + \frac{20}{21} : \frac{4}{3} = -\frac{88}{7} + 18 + \frac{20}{21} \cdot \frac{3}{4} = -\frac{88}{7} + 18 + \frac{5}{7} = -\frac{83}{7} + 18 = \frac{-83 + 126}{7} = \frac{43}{7} = 6\frac{1}{7}$ 8) $\frac{7}{9} : 1\frac{1}{6} + 2,7 : (-0,1) - 4\frac{1}{3} \cdot (-4) = \frac{7}{9} : \frac{7}{6} + 2,7 : (-0,1) - \frac{13}{3} \cdot (-4) = \frac{7}{9} \cdot \frac{6}{7} - 27 + \frac{52}{3} = \frac{2}{3} - 27 + \frac{52}{3} = \frac{54}{3} - 27 = 18 - 27 = -9$ Надеюсь, теперь тебе всё понятно!