Решение

1. a) $$\frac{-3}{7} + \frac{6}{7} = \frac{-3 + 6}{7} = \frac{3}{7}$$
2. б) $$\frac{-5}{11} + \frac{3}{11} = \frac{-5 + 3}{11} = \frac{-2}{11}$$
3. в) $$\frac{3}{4} + (\frac{-1}{6}) = \frac{3}{4} - \frac{1}{6} = \frac{3 \cdot 3}{4 \cdot 3} - \frac{1 \cdot 2}{6 \cdot 2} = \frac{9}{12} - \frac{2}{12} = \frac{9 - 2}{12} = \frac{7}{12}$$
4. г) $$-1 + \frac{4}{7} = \frac{-1 \cdot 7}{7} + \frac{4}{7} = \frac{-7}{7} + \frac{4}{7} = \frac{-7 + 4}{7} = \frac{-3}{7}$$
5. д) $$-4 + 2\frac{7}{8} = -4 + \frac{2 \cdot 8 + 7}{8} = -4 + \frac{16 + 7}{8} = -4 + \frac{23}{8} = \frac{-4 \cdot 8}{8} + \frac{23}{8} = \frac{-32}{8} + \frac{23}{8} = \frac{-32 + 23}{8} = \frac{-9}{8} = -1\frac{1}{8}$$
6. е) $$10 + (-8\frac{5}{13}) = 10 - 8\frac{5}{13} = 10 - \frac{8 \cdot 13 + 5}{13} = 10 - \frac{104 + 5}{13} = 10 - \frac{109}{13} = \frac{10 \cdot 13}{13} - \frac{109}{13} = \frac{130}{13} - \frac{109}{13} = \frac{130 - 109}{13} = \frac{21}{13} = 1\frac{8}{13}$$
7. ж) $$8\frac{2}{7} + (-7\frac{5}{14}) = 8\frac{2}{7} - 7\frac{5}{14} = \frac{8 \cdot 7 + 2}{7} - \frac{7 \cdot 14 + 5}{14} = \frac{56 + 2}{7} - \frac{98 + 5}{14} = \frac{58}{7} - \frac{103}{14} = \frac{58 \cdot 2}{7 \cdot 2} - \frac{103}{14} = \frac{116}{14} - \frac{103}{14} = \frac{116 - 103}{14} = \frac{13}{14}$$
8. з) $$-9\frac{1}{7} + 8,5 = -9\frac{1}{7} + \frac{85}{10} = -9\frac{1}{7} + \frac{17}{2} = \frac{-9 \cdot 7 - 1}{7} + \frac{17}{2} = \frac{-63 - 1}{7} + \frac{17}{2} = \frac{-64}{7} + \frac{17}{2} = \frac{-64 \cdot 2}{7 \cdot 2} + \frac{17 \cdot 7}{2 \cdot 7} = \frac{-128}{14} + \frac{119}{14} = \frac{-128 + 119}{14} = \frac{-9}{14}$$