277. Найдите сумму: 1) 5 7/8 + 6 3/10; 2) 6 3/8 + 2 5/9.

1. \(5\frac{7}{8}+6\frac{3}{10}=11+\frac{7}{8}+\frac{3}{10}=11+\frac{35}{40}+\frac{12}{40}=11\frac{47}{40}=12\frac{7}{40}\).
2. \(6\frac{3}{8}+2\frac{5}{9}=8+\frac{3}{8}+\frac{5}{9}=8+\frac{27}{72}+\frac{40}{72}=8\frac{67}{72}\).

Ответ: 1) \(12\frac{7}{40}\); 2) \(8\frac{67}{72}\).