1.12 в) $$8\frac{1}{7} - 4\frac{1}{7} : 3\frac{5}{8}$$

$$\begin{aligned} &8\frac{1}{7} - 4\frac{1}{7} : 3\frac{5}{8} = \\ &= \frac{57}{7} - \frac{29}{7} : \frac{29}{8} = \\ &= \frac{57}{7} - \frac{29}{7} \cdot \frac{8}{29} = \\ &= \frac{57}{7} - \frac{8}{7} = \\ &= \frac{49}{7} = \\ &= 7 \end{aligned}$$ Ответ: 7