№2. Выполните действия: 1) \(\left(\frac{6}{9}+\frac{3}{9}\right)\cdot\frac{8}{13}\); 2) \(\left(\frac{5}{71}-\frac{2}{71}\right)\cdot\frac{11}{3}\); 3) \(2\cdot\frac{1}{8}+\frac{4}{12}\cdot\frac{3}{7}\); 4) \(\left(\frac{2}{3}\right)^2+\frac{13}{21}\cdot\frac{7}{26}-\frac{5}{78}\); 5) \(\frac{2}{5}\cdot\left(\frac{11}{14}-\frac{3}{7}\right)\); 6) \(9\frac{3}{7}\cdot\frac{5}{22}\); 7) \(6\frac{3}{8}\cdot\frac{16}{77}\); 8) \(2\frac{1}{3}\cdot1\frac{1}{5}\).

1. \(\left(\frac{6}{9}+\frac{3}{9}\right)\cdot\frac{8}{13}=1\cdot\frac{8}{13}=\frac{8}{13}\).
2. \(\left(\frac{5}{71}-\frac{2}{71}\right)\cdot\frac{11}{3}=\frac{3}{71}\cdot\frac{11}{3}=\frac{11}{71}\).
3. \(2\cdot\frac{1}{8}+\frac{4}{12}\cdot\frac{3}{7}=\frac{1}{4}+\frac{1}{3}\cdot\frac{3}{7}=\frac{1}{4}+\frac{1}{7}=\frac{11}{28}\).
4. \(\left(\frac{2}{3}\right)^2+\frac{13}{21}\cdot\frac{7}{26}-\frac{5}{78}=\frac{4}{9}+\frac{1}{6}-\frac{5}{78}=\frac{104+39-15}{234}=\frac{128}{234}=\frac{64}{117}\).
5. \(\frac{2}{5}\cdot\left(\frac{11}{14}-\frac{3}{7}\right)=\frac{2}{5}\cdot\frac{5}{14}=\frac{1}{7}\).
6. \(9\frac{3}{7}\cdot\frac{5}{22}=\frac{66}{7}\cdot\frac{5}{22}=\frac{15}{7}=2\frac{1}{7}\).
7. \(6\frac{3}{8}\cdot\frac{16}{77}=\frac{51}{8}\cdot\frac{16}{77}=\frac{102}{77}=\frac{6}{?}\). При сокращении: \(\frac{51\cdot2}{77}=\frac{102}{77}=\frac{6}{?}\); так как \(102=6\cdot17\), \(77=7\cdot11\), дробь не сокращается: \(\frac{102}{77}=1\frac{25}{77}\).
8. \(2\frac{1}{3}\cdot1\frac{1}{5}=\frac{7}{3}\cdot\frac{6}{5}=\frac{14}{5}=2\frac{4}{5}\).

Ответ: 1) \(\frac{8}{13}\); 2) \(\frac{11}{71}\); 3) \(\frac{11}{28}\); 4) \(\frac{64}{117}\); 5) \(\frac{1}{7}\); 6) \(2\frac{1}{7}\); 7) \(1\frac{25}{77}\); 8) \(2\frac{4}{5}\).