а) $$2+\frac{4}{7} = 2\frac{4}{7} = \frac{2\cdot7+4}{7} = \frac{18}{7}$$
б) $$10+\frac{20}{30} = 10+\frac{2}{3} = 10\frac{2}{3} = \frac{10\cdot3+2}{3} = \frac{32}{3}$$
в) $$34+\frac{46}{67} = 34\frac{46}{67} = \frac{34\cdot67+46}{67} = \frac{2324}{67}$$
Ответ: а) $$2\frac{4}{7} = \frac{18}{7}$$, б) $$10\frac{2}{3} = \frac{32}{3}$$, в) $$34\frac{46}{67} = \frac{2324}{67}$$.