50. Найдите сумму: 1) 9 3/4 + 3 1/6; 2) 11 7/12 + 6 11/18; 3) 7 8/15 + 8 17/20; 4) 7 3/8 + 9 7/16 + 11 7/12.

1. \(9\frac{3}{4}+3\frac{1}{6}=12+\frac{9}{12}+\frac{2}{12}=12\frac{11}{12}\).
2. \(11\frac{7}{12}+6\frac{11}{18}=17+\frac{21}{36}+\frac{22}{36}=17\frac{43}{36}=18\frac{7}{36}\).
3. \(7\frac{8}{15}+8\frac{17}{20}=15+\frac{32}{60}+\frac{51}{60}=16\frac{23}{60}\).
4. \(7\frac{3}{8}+9\frac{7}{16}+11\frac{7}{12}=27+\frac{18}{48}+\frac{21}{48}+\frac{28}{48}=27\frac{67}{48}=28\frac{19}{48}\).

Ответ: 1) \(12\frac{11}{12}\); 2) \(18\frac{7}{36}\); 3) \(16\frac{23}{60}\); 4) \(28\frac{19}{48}\).