2. Действия с обыкновенными дробями. 1) 1/5 + 53/50; 2) 9/4 + 8/5; 3) 1/10 + 6/15; 4) 1/5 − 47/10; 4) 1/2 − 9/10; 6) 11/12 − 5/18; 7) 9/5 · 2/3; 8) 15/4 · 6/5; 9) 2/3 · 9/8; 10) 6/5 : 4/11; 11) 12/5 : 15/2; 12) 6/11 : 3/22; 13) (13/30 − 11/20) · 9/5; 14) (17/15 − 1/12) · 20/3; 15) 14/5 · (3/14 − 5/28); 16) (11/18 + 2/9) : 5/48; 17) (11/10 − 4/11) : 15/44; 18) (6/8 − 3/16) : 3/32.

1. \(\frac{1}{5}+\frac{53}{50}=\frac{10}{50}+\frac{53}{50}=\frac{63}{50}\).
2. \(\frac{9}{4}+\frac{8}{5}=\frac{45}{20}+\frac{32}{20}=\frac{77}{20}\).
3. \(\frac{1}{10}+\frac{6}{15}=\frac{1}{10}+\frac{2}{5}=\frac{1}{2}\).
4. \(\frac{1}{5}-\frac{47}{10}=\frac{2}{10}-\frac{47}{10}=-\frac{45}{10}=-\frac{9}{2}\).
5. \(\frac{1}{2}-\frac{9}{10}=\frac{5}{10}-\frac{9}{10}=-\frac{4}{10}=-\frac{2}{5}\).
6. \(\frac{11}{12}-\frac{5}{18}=\frac{33}{36}-\frac{10}{36}=\frac{23}{36}\).
7. \(\frac{9}{5}\cdot\frac{2}{3}=\frac{18}{15}=\frac{6}{5}\).
8. \(\frac{15}{4}\cdot\frac{6}{5}=\frac{90}{20}=\frac{9}{2}\).
9. \(\frac{2}{3}\cdot\frac{9}{8}=\frac{18}{24}=\frac{3}{4}\).
10. \(\frac{6}{5}:\frac{4}{11}=\frac{6}{5}\cdot\frac{11}{4}=\frac{33}{10}\).
11. \(\frac{12}{5}:\frac{15}{2}=\frac{12}{5}\cdot\frac{2}{15}=\frac{8}{25}\).
12. \(\frac{6}{11}:\frac{3}{22}=\frac{6}{11}\cdot\frac{22}{3}=4\).
13. \(\left(\frac{13}{30}-\frac{11}{20}\right)\cdot\frac{9}{5}=\left(\frac{26}{60}-\frac{33}{60}\right)\cdot\frac{9}{5}=-\frac{7}{60}\cdot\frac{9}{5}=-\frac{21}{100}\).
14. \(\left(\frac{17}{15}-\frac{1}{12}\right)\cdot\frac{20}{3}=\left(\frac{68}{60}-\frac{5}{60}\right)\cdot\frac{20}{3}=\frac{21}{20}\cdot\frac{20}{3}=7\).
15. \(\frac{14}{5}\cdot\left(\frac{3}{14}-\frac{5}{28}\right)=\frac{14}{5}\cdot\frac{1}{28}=\frac{1}{10}\).
16. \(\left(\frac{11}{18}+\frac{2}{9}\right):\frac{5}{48}=\frac{5}{6}\cdot\frac{48}{5}=8\).
17. \(\left(\frac{11}{10}-\frac{4}{11}\right):\frac{15}{44}=\frac{81}{110}\cdot\frac{44}{15}=\frac{54}{25}\).
18. \(\left(\frac{6}{8}-\frac{3}{16}\right):\frac{3}{32}=\frac{9}{16}\cdot\frac{32}{3}=6\).

Ответ: 1) \(\frac{63}{50}\); 2) \(\frac{77}{20}\); 3) \(\frac{1}{2}\); 4) \(-\frac{9}{2}\); 4) \(-\frac{2}{5}\); 6) \(\frac{23}{36}\); 7) \(\frac{6}{5}\); 8) \(\frac{9}{2}\); 9) \(\frac{3}{4}\); 10) \(\frac{33}{10}\); 11) \(\frac{8}{25}\); 12) 4; 13) \(-\frac{21}{100}\); 14) 7; 15) \(\frac{1}{10}\); 16) 8; 17) \(\frac{54}{25}\); 18) 6.