1) 1/3 + 2/5

$$\frac{1}{3} + \frac{2}{5} = \frac{1*5}{3*5} + \frac{2*3}{5*3} = \frac{5}{15} + \frac{6}{15} = \frac{5+6}{15} = \frac{11}{15}$$
Ответ: $$\frac{11}{15}$$