810. Вычислите: а) 1/2 + 1/2; б) 1/7 + 5/7; в) 3/5 + 4/5; г) 1 1/3 + 2/3; д) 2 7/9 + 4/9; е) 3 2/5 + 12 4/5.

1. \(\frac{1}{2}+\frac{1}{2}=\frac{2}{2}=1\).
2. \(\frac{1}{7}+\frac{5}{7}=\frac{6}{7}\).
3. \(\frac{3}{5}+\frac{4}{5}=\frac{7}{5}=1\frac{2}{5}\).
4. \(1\frac{1}{3}+\frac{2}{3}=1+1=2\).
5. \(2\frac{7}{9}+\frac{4}{9}=2+\frac{11}{9}=3\frac{2}{9}\).
6. \(3\frac{2}{5}+12\frac{4}{5}=15+\frac{6}{5}=16\frac{1}{5}\).

Ответ: а) 1; б) \(\frac{6}{7}\); в) \(1\frac{2}{5}\); г) 2; д) \(3\frac{2}{9}\); е) \(16\frac{1}{5}\).