2 1 -- + -- = 7 6

$$\frac{2}{7} + \frac{1}{6} = \frac{2 \cdot 6}{7 \cdot 6} + \frac{1 \cdot 7}{6 \cdot 7} = \frac{12}{42} + \frac{7}{42} = \frac{19}{42}$$

Ответ: $$\frac{19}{42}$$