2. Найдите сумму:

2. Найдём сумму:

1. \( \frac{1}{5} + \frac{2}{11} + \frac{4}{5} + \frac{7}{11} = \left( \frac{1}{5} + \frac{4}{5} \right) + \left( \frac{2}{11} + \frac{7}{11} \right) = \frac{1+4}{5} + \frac{2+7}{11} = \frac{5}{5} + \frac{9}{11} = 1 + \frac{9}{11} = 1\frac{9}{11} \)
2. \( \frac{2}{3} + \frac{3}{18} + \frac{5}{6} + \frac{7}{18} = \frac{2 × 6}{3 × 6} + \frac{3}{18} + \frac{5 × 3}{6 × 3} + \frac{7}{18} = \frac{12}{18} + \frac{3}{18} + \frac{15}{18} + \frac{7}{18} = \frac{12+3+15+7}{18} = \frac{37}{18} = 2\frac{1}{18} \)