1. Вычисли: 1) 3/5 + 4/5; 2) 1 − 2/7; 3) 4 2/5 + 2 1/5; 4) 3 8/11 − 1 6/11.

1. \(\frac{3}{5}+\frac{4}{5}=\frac{7}{5}=1\frac{2}{5}\).
2. \(1-\frac{2}{7}=\frac{7}{7}-\frac{2}{7}=\frac{5}{7}\).
3. \(4\frac{2}{5}+2\frac{1}{5}=6\frac{3}{5}\).
4. \(3\frac{8}{11}-1\frac{6}{11}=2\frac{2}{11}\).

Ответ: 1) \(1\frac{2}{5}\); 2) \(\frac{5}{7}\); 3) \(6\frac{3}{5}\); 4) \(2\frac{2}{11}\).