12 6 3+2= 17 17

3 12/17 + 2 6/17 = 5 18/17 = 6 1/17

$$3 \frac{12}{17} + 2 \frac{6}{17} = (3 + 2) + (\frac{12}{17} + \frac{6}{17}) = 5 + \frac{12+6}{17} = 5 + \frac{18}{17} = 5 + 1 \frac{1}{17} = 6 \frac{1}{17}$$

Ответ: $$6 \frac{1}{17}$$