811. Вычислите: а) 9/11 − 8/11; б) 6/7 − 2/7; в) 1 − 1/9; г) 12 − 1/3; д) 127 − 2/5; е) 193 − 4/9; ж) 13 3/4 − 1/2; з) 13 1/2 − 1/3; и) 15 4/5 − 8 2/5; к) 20 3/8 − 16 1/4; л) 3 1/6 − 1/3; м) 2 1/3 − 1/2; н) 10 1/5 − 2/5; о) 3/7 − 4/5; п) 3 1/2 − 2 2/3.

1. \(\frac{9}{11}-\frac{8}{11}=\frac{1}{11}\).
2. \(\frac{6}{7}-\frac{2}{7}=\frac{4}{7}\).
3. \(1-\frac{1}{9}=\frac{8}{9}\).
4. \(12-\frac{1}{3}=11\frac{2}{3}\).
5. \(127-\frac{2}{5}=126\frac{3}{5}\).
6. \(193-\frac{4}{9}=192\frac{5}{9}\).
7. \(13\frac{3}{4}-\frac{1}{2}=13\frac{1}{4}\).
8. \(13\frac{1}{2}-\frac{1}{3}=13\frac{1}{6}\).
9. \(15\frac{4}{5}-8\frac{2}{5}=7\frac{2}{5}\).
10. \(20\frac{3}{8}-16\frac{1}{4}=4\frac{1}{8}\).
11. \(3\frac{1}{6}-\frac{1}{3}=2\frac{5}{6}\).
12. \(2\frac{1}{3}-\frac{1}{2}=1\frac{5}{6}\).
13. \(10\frac{1}{5}-\frac{2}{5}=9\frac{4}{5}\).
14. \(\frac{3}{7}-\frac{4}{5}=\frac{15}{35}-\frac{28}{35}=-\frac{13}{35}\).
15. \(3\frac{1}{2}-2\frac{2}{3}=\frac{7}{2}-\frac{8}{3}=\frac{21-16}{6}=\frac{5}{6}\).

Ответ: а) \(\frac{1}{11}\); б) \(\frac{4}{7}\); в) \(\frac{8}{9}\); г) \(11\frac{2}{3}\); д) \(126\frac{3}{5}\); е) \(192\frac{5}{9}\); ж) \(13\frac{1}{4}\); з) \(13\frac{1}{6}\); и) \(7\frac{2}{5}\); к) \(4\frac{1}{8}\); л) \(2\frac{5}{6}\); м) \(1\frac{5}{6}\); н) \(9\frac{4}{5}\); о) \(-\frac{13}{35}\); п) \(\frac{5}{6}\).