Решение:
1. $$0,6 - \frac{14}{15} = \frac{6}{10} - \frac{14}{15} = \frac{3}{5} - \frac{14}{15} = \frac{9}{15} - \frac{14}{15} = -\frac{5}{15} = -\frac{1}{3}$$
2. $$-\frac{1}{3} \cdot \frac{6}{7} = -\frac{1 \cdot 6}{3 \cdot 7} = -\frac{1 \cdot 2}{1 \cdot 7} = -\frac{2}{7}$$
3. $$\frac{8}{35} - 0,8 = \frac{8}{35} - \frac{8}{10} = \frac{8}{35} - \frac{4}{5} = \frac{8}{35} - \frac{28}{35} = -\frac{20}{35} = -\frac{4}{7}$$
4. $$-2\frac{2}{3} = -\frac{8}{3}$$
5. $$(-\frac{4}{7}) : (-\frac{8}{3}) = \frac{4}{7} \cdot \frac{3}{8} = \frac{4 \cdot 3}{7 \cdot 8} = \frac{1 \cdot 3}{7 \cdot 2} = \frac{3}{14}$$
6. $$-\frac{2}{7} - \frac{3}{14} = -\frac{4}{14} - \frac{3}{14} = -\frac{7}{14} = -\frac{1}{2}$$
Ответ: **-1/2**