2. Выполните действия: а) 5/9 + 11/27; б) 2/3 − 3/5; в) 7 − 3 3/4; г) 4 5/6 + 8 4/15; д) 1 7/12 − 5/18; е) 2 1/8 − 1 9/20.

1. \(\dfrac{5}{9}+\dfrac{11}{27}=\dfrac{15}{27}+\dfrac{11}{27}=\dfrac{26}{27}\).
2. \(\dfrac{2}{3}-\dfrac{3}{5}=\dfrac{10}{15}-\dfrac{9}{15}=\dfrac{1}{15}\).
3. \(7-3\dfrac{3}{4}=7-3-\dfrac{3}{4}=3\dfrac{1}{4}\).
4. \(4\dfrac{5}{6}+8\dfrac{4}{15}=12+\dfrac{25}{30}+\dfrac{8}{30}=12+1\dfrac{1}{10}=13\dfrac{1}{10}\).
5. \(1\dfrac{7}{12}-\dfrac{5}{18}=\dfrac{19}{12}-\dfrac{5}{18}=\dfrac{57}{36}-\dfrac{10}{36}=\dfrac{47}{36}=1\dfrac{11}{36}\).
6. \(2\dfrac{1}{8}-1\dfrac{9}{20}=\dfrac{17}{8}-\dfrac{29}{20}=\dfrac{170}{80}-\dfrac{116}{80}=\dfrac{54}{80}=\dfrac{27}{40}\).

Ответ: а) \(\dfrac{26}{27}\); б) \(\dfrac{1}{15}\); в) \(3\dfrac{1}{4}\); г) \(13\dfrac{1}{10}\); д) \(1\dfrac{11}{36}\); е) \(\dfrac{27}{40}\).