2. Вычислите: 1) 5/6 + 2/7; 2) 11/25 − 3/10; 3) 15/16 − 3/4; 4) 3/20 + 7/15; 5) 13/16 − 7/12; 6) 9/14 + 5/21; 7) 16/35 − 5/14; 8) 2/5 + 1/3 − 7/30; 9) 3/4 − 2/9 + 5/36.

1. \(\frac{5}{6}+\frac{2}{7}=\frac{35}{42}+\frac{12}{42}=\frac{47}{42}=1\frac{5}{42}\).
2. \(\frac{11}{25}-\frac{3}{10}=\frac{22}{50}-\frac{15}{50}=\frac{7}{50}\).
3. \(\frac{15}{16}-\frac{3}{4}=\frac{15}{16}-\frac{12}{16}=\frac{3}{16}\).
4. \(\frac{3}{20}+\frac{7}{15}=\frac{9}{60}+\frac{28}{60}=\frac{37}{60}\).
5. \(\frac{13}{16}-\frac{7}{12}=\frac{39}{48}-\frac{28}{48}=\frac{11}{48}\).
6. \(\frac{9}{14}+\frac{5}{21}=\frac{27}{42}+\frac{10}{42}=\frac{37}{42}\).
7. \(\frac{16}{35}-\frac{5}{14}=\frac{32}{70}-\frac{25}{70}=\frac{7}{70}=\frac{1}{10}\).
8. \(\frac{2}{5}+\frac{1}{3}-\frac{7}{30}=\frac{12}{30}+\frac{10}{30}-\frac{7}{30}=\frac{15}{30}=\frac{1}{2}\).
9. \(\frac{3}{4}-\frac{2}{9}+\frac{5}{36}=\frac{27}{36}-\frac{8}{36}+\frac{5}{36}=\frac{24}{36}=\frac{2}{3}\).

Ответ: 1) 1 5/42; 2) 7/50; 3) 3/16; 4) 37/60; 5) 11/48; 6) 37/42; 7) 1/10; 8) 1/2; 9) 2/3.