2)5\frac{5}{6} \cdot 8\frac{2}{5}-4\frac{5}{6} \cdot 1\frac{5}{6}+6\frac{5}{6} \cdot 8\frac{2}{5}-7\frac{3}{6} \cdot 1\frac{5}{6}.

2) $$5\frac{5}{6} \cdot 8\frac{2}{5}-4\frac{5}{6} \cdot 1\frac{5}{6}+6\frac{5}{6} \cdot 8\frac{2}{5}-7\frac{3}{6} \cdot 1\frac{5}{6} = \frac{35}{6} \cdot \frac{42}{5} - \frac{29}{6} \cdot \frac{11}{6} + \frac{41}{6} \cdot \frac{42}{5} - \frac{45}{6} \cdot \frac{11}{6} = \frac{35}{6} \cdot \frac{42}{5} + \frac{41}{6} \cdot \frac{42}{5} - \frac{29}{6} \cdot \frac{11}{6} - \frac{45}{6} \cdot \frac{11}{6} = \frac{42}{5}(\frac{35}{6} + \frac{41}{6}) - \frac{11}{6} (\frac{29}{6} + \frac{45}{6}) = \frac{42}{5} \cdot \frac{76}{6} - \frac{11}{6} \cdot \frac{74}{6} = \frac{42}{5} \cdot \frac{38}{3} - \frac{11}{6} \cdot \frac{37}{3} = \frac{1596}{15} - \frac{407}{18} = \frac{532}{5} - \frac{407}{18} = \frac{9576 - 2035}{90} = \frac{7541}{90} = 83\frac{71}{90}$$ Ответ: $$83\frac{71}{90}$$