Вариант 2. Выполните сложение: а) 4/5 + 3/7; б) 5/12 + 4/45; в) 8/33 + 2/11; г) 12/17 + 27/34; д) 5/12 + 4/45; е) 8/21 + 7/18.

1. \(\frac{4}{5}+\frac{3}{7}=\frac{28}{35}+\frac{15}{35}=\frac{43}{35}\).
2. \(\frac{5}{12}+\frac{4}{45}=\frac{75}{180}+\frac{16}{180}=\frac{91}{180}\).
3. \(\frac{8}{33}+\frac{2}{11}=\frac{8}{33}+\frac{6}{33}=\frac{14}{33}\).
4. \(\frac{12}{17}+\frac{27}{34}=\frac{24}{34}+\frac{27}{34}=\frac{51}{34}\).
5. \(\frac{8}{21}+\frac{7}{18}=\frac{48}{126}+\frac{49}{126}=\frac{97}{126}\).

Ответ: а) \(\frac{43}{35}\); б) \(\frac{91}{180}\); в) \(\frac{14}{33}\); г) \(\frac{51}{34}\); е) \(\frac{97}{126}\).