6 1 6 3 1 3 7-1-+3--. 711711

$$7\frac{6}{7} \cdot 1\frac{6}{11} + 3\frac{1}{7} \cdot \frac{3}{11} = \frac{55}{7} \cdot \frac{17}{11} + \frac{22}{7} \cdot \frac{3}{11} = \frac{5 \cdot 17}{7} + \frac{2 \cdot 3}{7} = \frac{85}{7} + \frac{6}{7} = \frac{91}{7} = 13$$

Ответ: $$13$$