Вычислить сумму. 11/30+7/12, 1/6+1/10+1/15, 5/12+2/9+1/18, 1/2+1/3+1/9

Решите задачу:

$\frac{11}{30} + \frac{7}{12} = \frac{22 + 35}{60} = \frac{57}{60} = \frac{19}{20} \\ \\ \frac{1}{6} + \frac{1}{10} + \frac{1}{15} = \frac{5 + 3 + 2}{30} = \frac{10}{30} = \frac{1}{3} \\ \\ \frac{5}{12} + \frac{2}{9} + \frac{1}{18} = \frac{15 + 8 + 2}{36} = \frac{25}{36}\\ \\ \frac{1}{2} + \frac{1}{3} + \frac{1}{9} = \frac{9 + 6 + 2}{18} = \frac{17}{18}$