2 1/3 : (5/8 - 8/3) - 2 * 1 3/7.

Решим задания из домашней работы (1 вариант). 1) $2 \frac{1}{3} : (\frac{5}{8} - \frac{8}{3}) - 2 \cdot 1 \frac{3}{7}$ $\frac{7}{3} : (\frac{15}{24} - \frac{64}{24}) - 2 \cdot \frac{10}{7} = \frac{7}{3} : (-\frac{49}{24}) - \frac{20}{7} = \frac{7}{3} \cdot (-\frac{24}{49}) - \frac{20}{7} = -\frac{8}{7} - \frac{20}{7} = -\frac{28}{7} = -4$ 2) $(7 - 1 \frac{5}{9} : \frac{7}{24}) : \frac{20}{27}$ $(7 - \frac{14}{9} \cdot \frac{24}{7}) : \frac{20}{27} = (7 - \frac{2}{3} \cdot \frac{8}{1}) : \frac{20}{27} = (7 - \frac{16}{3}) : \frac{20}{27} = (\frac{21-16}{3}) : \frac{20}{27} = \frac{5}{3} \cdot \frac{27}{20} = \frac{1}{1} \cdot \frac{9}{4} = 2,25$ 3) $1 \frac{31}{35} : (2 - \frac{8}{9} : 1 \frac{19}{45})$ $\frac{66}{35} : (2 - \frac{8}{9} : \frac{64}{45}) = \frac{66}{35} : (2 - \frac{8}{9} \cdot \frac{45}{64}) = \frac{66}{35} : (2 - \frac{1}{1} \cdot \frac{5}{8}) = \frac{66}{35} : (\frac{16-5}{8}) = \frac{66}{35} : \frac{11}{8} = \frac{66}{35} \cdot \frac{8}{11} = \frac{6}{35} \cdot 8 = \frac{48}{35} = 1 \frac{13}{35}$ 4) $(5 \frac{1}{16} - 1 \frac{1}{8}) (\frac{5}{6} + \frac{3}{14})$ $(\frac{81}{16} - \frac{9}{8}) (\frac{35}{42} + \frac{9}{42}) = (\frac{81}{16} - \frac{18}{16}) (\frac{44}{42}) = \frac{63}{16} \cdot \frac{22}{21} = \frac{3}{8} \cdot \frac{11}{1} = \frac{33}{8} = 4 \frac{1}{8}$ 5) $(2 \frac{13}{48} + 2 \frac{5}{12}) : 3 \frac{3}{4} - 9 \frac{3}{4} : 12$ $(2 \frac{13}{48} + 2 \frac{20}{48}) : \frac{15}{4} - \frac{39}{4} : 12 = (4 \frac{33}{48}) : \frac{15}{4} - \frac{39}{48} = \frac{225}{48} \cdot \frac{4}{15} - \frac{13}{16} = \frac{15}{12} \cdot 1 - \frac{13}{16} = \frac{5}{4} - \frac{13}{16} = \frac{20-13}{16} = \frac{7}{16}$ 6) $4 \frac{1}{3} \cdot 5 + 2,4 : (-0,1) - \frac{14}{15} : 1 \frac{2}{5}$ $\frac{13}{3} \cdot 5 + 24 : (-1) - \frac{14}{15} : \frac{7}{5} = \frac{65}{3} - 24 - \frac{14}{15} \cdot \frac{5}{7} = 21 \frac{2}{3} - 24 - \frac{2}{3} = -3 - \frac{2}{3} = -3 \frac{2}{3}$ 6) $3 \frac{1}{7} \cdot (-4) - 1,8 : (-0,1) + \frac{20}{21} : 1 \frac{2}{3}$ $\frac{22}{7} \cdot (-4) - (18) + \frac{20}{21} : \frac{5}{3} = -\frac{88}{7} - 18 + \frac{20}{21} \cdot \frac{3}{5} = -12 \frac{4}{7} - 18 + \frac{4}{7} = -30 - \frac{4}{7} + \frac{4}{7} = -30$ 6) $\frac{7}{9} : 1 \frac{1}{6} + 2,7 : (-0,1) - 4 \frac{1}{3} \cdot (-4)$ $\frac{7}{9} : \frac{7}{6} + 27 : (-1) - \frac{13}{3} \cdot (-4) = \frac{7}{9} \cdot \frac{6}{7} - 27 + \frac{52}{3} = \frac{2}{3} - 27 + 17 \frac{1}{3} = 17 \frac{3}{3} - 27 = 18 - 27 = -9$