Выполним сложение дробей:
- $$1 \frac{2}{5} + 3 \frac{2}{5} = (1+3) + (\frac{2}{5} + \frac{2}{5}) = 4 + \frac{2+2}{5} = 4 + \frac{4}{5} = 4\frac{4}{5}$$
- $$3 \frac{2}{7} + 6 \frac{4}{7} = (3+6) + (\frac{2}{7} + \frac{4}{7}) = 9 + \frac{2+4}{7} = 9 + \frac{6}{7} = 9\frac{6}{7}$$
- $$2 \frac{2}{9} + 9 \frac{5}{9} = (2+9) + (\frac{2}{9} + \frac{5}{9}) = 11 + \frac{2+5}{9} = 11 + \frac{7}{9} = 11\frac{7}{9}$$
Ответ: 1) $$4\frac{4}{5}$$, 2) $$9\frac{6}{7}$$, 3) $$11\frac{7}{9}$$