4. Сложите дроби. a) 2+3+9= 17 1717 6)++ 131 555 в) 3+5+6+1= 4 11 11 4

a) $$\frac{2}{17} + \frac{3}{17} + \frac{9}{17} = \frac{14}{17}$$

б) $$\frac{1}{5} + \frac{3}{5} + \frac{1}{5} = \frac{5}{5} = 1$$

в) $$\frac{3}{4} + \frac{5}{11} + \frac{6}{11} + \frac{1}{4} = (\frac{3}{4} + \frac{1}{4}) + (\frac{5}{11} + \frac{6}{11}) = \frac{4}{4} + \frac{11}{11} = 1 + 1 = 2$$

Ответ: a) $$\frac{14}{17}$$, б) $$1$$, в) $$2$$