3) (-3 3/10 - 1 8/15) : (-1 2/27);

1) $(-3 \frac{3}{10} - 1 \frac{8}{15}) : (-1 \frac{2}{27}) = (-\frac{33}{10} - \frac{23}{15}) : (-\frac{29}{27}) = (-\frac{99}{30} - \frac{46}{30}) : (-\frac{29}{27}) = (-\frac{145}{30}) : (-\frac{29}{27}) = \frac{29}{6} \cdot \frac{27}{29} = \frac{9}{2} = 4.5 2) $(\frac{9}{20} - \frac{7}{8}) : (-\frac{7}{45} - \frac{2}{9}) = (\frac{18}{40} - \frac{35}{40}) : (-\frac{7}{45} - \frac{10}{45}) = (-\frac{17}{40}) : (-\frac{17}{45}) = \frac{17}{40} \cdot \frac{45}{17} = \frac{45}{40} = \frac{9}{8} = 1.125 3) $(-4 \frac{1}{12} + 3 \frac{9}{10}) : 3 \frac{3}{10} = (-\frac{49}{12} + \frac{39}{10}) : \frac{33}{10} = (-\frac{245}{60} + \frac{234}{60}) : \frac{33}{10} = (-\frac{11}{60}) : \frac{33}{10} = (-\frac{11}{60}) \cdot \frac{10}{33} = -\frac{1}{6} \cdot \frac{1}{3} = -\frac{1}{18} 4) $(\frac{11}{14} - \frac{5}{6}) : (\frac{11}{14} - \frac{3}{4}) = (\frac{33}{42} - \frac{35}{42}) : (\frac{22}{28} - \frac{21}{28}) = (-\frac{2}{42}) : \frac{1}{28} = (-\frac{1}{21}) : \frac{1}{28} = -\frac{1}{21} \cdot 28 = -\frac{28}{21} = -\frac{4}{3} = -1 \frac{1}{3}