2. Выполните действия: 1) 5/26 + 11/26 − 7/26; 2) 5 8/21 − 2 3/21 + 1 5/21; 3) 1 − 15/17; 4) 4 1/6 : 5/12.

1. \(\frac{5}{26}+\frac{11}{26}-\frac{7}{26}=\frac{5+11-7}{26}=\frac{9}{26}\).
2. \(5\frac{8}{21}-2\frac{3}{21}+1\frac{5}{21}=4+\frac{8-3+5}{21}=4\frac{10}{21}\).
3. \(1-\frac{15}{17}=\frac{17}{17}-\frac{15}{17}=\frac{2}{17}\).
4. \(4\frac{1}{6}:\frac{5}{12}=\frac{25}{6}\cdot\frac{12}{5}=10\).

Ответ: 1) \(\frac{9}{26}\); 2) \(4\frac{10}{21}\); 3) \(\frac{2}{17}\); 4) 10.