Ответ:

  1. а) \(\frac{1}{3}+\frac{5}{6}=\frac{2}{6}+\frac{5}{6}=\frac{7}{6}=1\frac{1}{6}\).

    б) \(\frac{5}{7}-\frac{1}{14}=\frac{10}{14}-\frac{1}{14}=\frac{9}{14}\).

    в) \(2\frac{2}{3}+5\frac{5}{12}=2\frac{8}{12}+5\frac{5}{12}=8\frac{13}{12}=9\frac{1}{12}\).

  2. а) \(\frac{3}{11}-\frac{1}{13}=\frac{39}{143}-\frac{11}{143}=\frac{28}{143}\).

    б) \(\frac{7}{20}+\frac{2}{3}=\frac{21}{60}+\frac{40}{60}=\frac{61}{60}=1\frac{1}{60}\).

    в) \(3\frac{2}{15}-1\frac{1}{7}=\frac{47}{15}-\frac{8}{7}=\frac{329-120}{105}=\frac{209}{105}=1\frac{104}{105}\).

  3. а) \(\frac{5}{34}-\frac{41}{51}=\frac{15}{102}-\frac{82}{102}=-\frac{67}{102}\).

    б) \(3\frac{1}{30}-5\frac{7}{90}=\frac{273}{90}-\frac{457}{90}=-\frac{184}{90}=-\frac{92}{45}=-2\frac{2}{45}\).

    в) \(6\frac{1}{7}-10\frac{3}{14}=\frac{86}{14}-\frac{143}{14}=-\frac{57}{14}=-4\frac{1}{14}\).

Ответ: 1) а) \(1\frac{1}{6}\); б) \(\frac{9}{14}\); в) \(9\frac{1}{12}\). 2) а) \(\frac{28}{143}\); б) \(1\frac{1}{60}\); в) \(1\frac{104}{105}\). 3) а) \(-\frac{67}{102}\); б) \(-2\frac{2}{45}\); в) \(-4\frac{1}{14}\).