a) $$2 + \frac{4}{7} = 2\frac{4}{7} = \frac{2 \cdot 7 + 4}{7} = \frac{18}{7};$$
б) $$10 + \frac{20}{30} = 10\frac{20}{30} = 10\frac{2}{3} = \frac{10 \cdot 3 + 2}{3} = \frac{32}{3};$$
в) $$34 + \frac{46}{67} = 34\frac{46}{67} = \frac{34 \cdot 67 + 46}{67} = \frac{2324}{67}.$$
Ответ: а) $$\frac{18}{7}$$; б) $$\frac{32}{3}$$; в) $$\frac{2324}{67}$$