Вычислите: а) 3/4 − 2/7; б) 1/2 + 3/7; в) 2/9 + 3/7; г) 8/9 − 1/2; а) 9/10 − 1/15; б) 5/16 + 5/12; в) 2/15 + 3/20; г) 14/15 − 7/25.

1. \(\frac{3}{4}-\frac{2}{7}=\frac{21}{28}-\frac{8}{28}=\frac{13}{28}\).
2. \(\frac{1}{2}+\frac{3}{7}=\frac{7}{14}+\frac{6}{14}=\frac{13}{14}\).
3. \(\frac{2}{9}+\frac{3}{7}=\frac{14}{63}+\frac{27}{63}=\frac{41}{63}\).
4. \(\frac{8}{9}-\frac{1}{2}=\frac{16}{18}-\frac{9}{18}=\frac{7}{18}\).
5. \(\frac{9}{10}-\frac{1}{15}=\frac{27}{30}-\frac{2}{30}=\frac{25}{30}=\frac{5}{6}\).
6. \(\frac{5}{16}+\frac{5}{12}=\frac{15}{48}+\frac{20}{48}=\frac{35}{48}\).
7. \(\frac{2}{15}+\frac{3}{20}=\frac{8}{60}+\frac{9}{60}=\frac{17}{60}\).
8. \(\frac{14}{15}-\frac{7}{25}=\frac{70}{75}-\frac{21}{75}=\frac{49}{75}\).

Ответ: а) \(\frac{13}{28}\), \(\frac{5}{6}\); б) \(\frac{13}{14}\), \(\frac{35}{48}\); в) \(\frac{41}{63}\), \(\frac{17}{60}\); г) \(\frac{7}{18}\), \(\frac{49}{75}\).