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

3) $\left(-3\frac{3}{10} - 1\frac{8}{15}\right) : \left(-1\frac{2}{27}\right) = \left(-\frac{33}{10} - \frac{23}{15}\right) : \left(-\frac{29}{27}\right) = \left(-\frac{99}{30} - \frac{46}{30}\right) : \left(-\frac{29}{27}\right) = \left(-\frac{145}{30}\right) : \left(-\frac{29}{27}\right) = \left(-\frac{29}{6}\right) : \left(-\frac{29}{27}\right) = \frac{29}{6} \cdot \frac{27}{29} = \frac{27}{6} = 4,5$ 4) $\left(\frac{9}{20} - \frac{7}{8}\right) : \left(-\frac{7}{45} - \frac{2}{9}\right) = \left(\frac{18}{40} - \frac{35}{40}\right) : \left(-\frac{7}{45} - \frac{10}{45}\right) = \left(-\frac{17}{40}\right) : \left(-\frac{17}{45}\right) = \frac{17}{40} \cdot \frac{45}{17} = \frac{45}{40} = 1,125$ 3) $\left(-4\frac{1}{12} + 3\frac{9}{10}\right) : 3\frac{3}{10} = \left(-\frac{49}{12} + \frac{39}{10}\right) : \frac{33}{10} = \left(-\frac{245}{60} + \frac{234}{60}\right) : \frac{33}{10} = \left(-\frac{11}{60}\right) : \frac{33}{10} = -\frac{11}{60} \cdot \frac{10}{33} = -\frac{1}{6} \cdot \frac{1}{3} = -\frac{1}{18}$ 4) $\left(\frac{11}{14} - \frac{5}{6}\right) : \left(\frac{11}{14} - \frac{3}{4}\right) = \left(\frac{33}{42} - \frac{35}{42}\right) : \left(\frac{22}{28} - \frac{21}{28}\right) = \left(-\frac{2}{42}\right) : \frac{1}{28} = \left(-\frac{1}{21}\right) \cdot 28 = -\frac{28}{21} = -1\frac{1}{3}$