2/3 + 3,4

$$2/3 + 3,4 = 2/3 + 34/10 = 2/3 + 17/5 = (2 \cdot 5)/(3 \cdot 5) + (17 \cdot 3)/(5 \cdot 3) = 10/15 + 51/15 = 61/15 = 4 \frac{1}{15}$$








Ответ: $$4 \frac{1}{15}$$