3. Вычислите: 1) 1 5/7 + 2 3/7; 2) 6 1/3 − 2 2/3; 3) 5 2/5 − 3 3/5.

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

2. \(6\frac{1}{3}-2\frac{2}{3}=5\frac{4}{3}-2\frac{2}{3}=3\frac{2}{3}\).

3. \(5\frac{2}{5}-3\frac{3}{5}=4\frac{7}{5}-3\frac{3}{5}=1\frac{4}{5}\).

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