1. Выполните действия: a) \frac{2}{11} + \frac{5}{11}; б) \frac{1}{6} + \frac{4}{8}; в) \frac{6}{15} - \frac{4}{15}; г) \frac{11}{25} - \frac{3}{25}; д) \frac{3}{9} + \frac{2}{9} + \frac{4}{9}; e) \frac{5}{18} + \frac{12}{18} - \frac{9}{18}; ж) \frac{12}{19} - \frac{1}{19} - \frac{5}{19}; з) \frac{25}{23} - \frac{10}{23} + \frac{3}{23}

Выполним действия:

1. \(\frac{2}{11} + \frac{5}{11} = \frac{2+5}{11} = \frac{7}{11}\)
2. \(\frac{1}{6} + \frac{4}{8} = \frac{1}{6} + \frac{1}{2} = \frac{1\cdot4 + 1 \cdot 12}{24} = \frac{4+12}{24} = \frac{16}{24} = \frac{2}{3}\)
3. \(\frac{6}{15} - \frac{4}{15} = \frac{6-4}{15} = \frac{2}{15}\)
4. \(\frac{11}{25} - \frac{3}{25} = \frac{11-3}{25} = \frac{8}{25}\)
5. \(\frac{3}{9} + \frac{2}{9} + \frac{4}{9} = \frac{3+2+4}{9} = \frac{9}{9} = 1\)
6. \(\frac{5}{18} + \frac{12}{18} - \frac{9}{18} = \frac{5+12-9}{18} = \frac{8}{18} = \frac{4}{9}\)
7. \(\frac{12}{19} - \frac{1}{19} - \frac{5}{19} = \frac{12-1-5}{19} = \frac{6}{19}\)
8. \(\frac{25}{23} - \frac{10}{23} + \frac{3}{23} = \frac{25-10+3}{23} = \frac{18}{23}\)

Ответ: а) \(\frac{7}{11}\); б) \(\frac{2}{3}\); в) \(\frac{2}{15}\); г) \(\frac{8}{25}\); д) 1; e) \(\frac{4}{9}\); ж) \(\frac{6}{19}\); з) \(\frac{18}{23}\)