а) 8$$\frac{1}{6}$$: 1$$\frac{1}{6}$$- 6$$\frac{2}{3}$$ = $$\frac{49}{6}$$ : $$\frac{7}{6}$$ - $$\frac{20}{3}$$ = $$\frac{49}{6}$$\cdot$$\frac{6}{7}$$ - $$\frac{20}{3}$$ = 7 - $$\frac{20}{3}$$ = $$\frac{21}{3}$$ - $$\frac{20}{3}$$ = $$\frac{1}{3}$$
Ответ: $$\frac{1}{3}$$