1 Выполните сложение: 3 6 a)-+; 7 5 3 б) -— + —; 11 11' 3 в) - + (- 4 г) -1+; 4 7 д) -4 + 2; 8 1 6 е) 10+(-8); 13 ж) 8+(-); 14 1 з)-9/+8,5. 7

1. a) $$-\frac{3}{7} + \frac{6}{7} = \frac{-3 + 6}{7} = \frac{3}{7}$$
2. б) $$\frac{-5}{11} + \frac{3}{11} = \frac{-5+3}{11} = \frac{-2}{11} = -\frac{2}{11}$$
3. в) $$\frac{3}{4} + (-\frac{1}{6}) = \frac{3}{4} - \frac{1}{6} = \frac{3 \cdot 3}{4 \cdot 3} - \frac{1 \cdot 2}{6 \cdot 2} = \frac{9}{12} - \frac{2}{12} = \frac{7}{12}$$
4. г) $$-1 + \frac{4}{7} = -\frac{7}{7} + \frac{4}{7} = \frac{-7+4}{7} = \frac{-3}{7} = -\frac{3}{7}$$
5. д) $$-4 + 2\frac{7}{8} = -4 + \frac{2 \cdot 8 + 7}{8} = -4 + \frac{16 + 7}{8} = -4 + \frac{23}{8} = -4 + 2\frac{7}{8} = -\frac{4 \cdot 8}{8} + \frac{23}{8} = \frac{-32 + 23}{8} = \frac{-9}{8} = -\frac{9}{8} = -1\frac{1}{8}$$
6. е) $$10 + (-8\frac{5}{13}) = 10 - 8\frac{5}{13} = 10 - \frac{8 \cdot 13 + 5}{13} = 10 - \frac{104 + 5}{13} = 10 - \frac{109}{13} = \frac{10 \cdot 13}{13} - \frac{109}{13} = \frac{130 - 109}{13} = \frac{21}{13} = 1\frac{8}{13}$$
7. ж) $$8\frac{2}{7} + (-\frac{5}{14}) = \frac{8 \cdot 7 + 2}{7} - \frac{5}{14} = \frac{56 + 2}{7} - \frac{5}{14} = \frac{58}{7} - \frac{5}{14} = \frac{58 \cdot 2}{7 \cdot 2} - \frac{5}{14} = \frac{116}{14} - \frac{5}{14} = \frac{116 - 5}{14} = \frac{111}{14} = 7\frac{13}{14}$$
8. з) $$-9\frac{1}{7} + 8,5 = -\frac{9 \cdot 7 + 1}{7} + 8,5 = -\frac{63 + 1}{7} + 8,5 = -\frac{64}{7} + 8,5 = -9\frac{1}{7} + 8,5 = -9,14 + 8,5 = -0,64$$

Ответ: a) $$\frac{3}{7}$$; б) $$\frac{-2}{11}$$; в) $$\frac{7}{12}$$; г) $$\frac{-3}{7}$$; д) $$-1\frac{1}{8}$$; е) $$1\frac{8}{13}$$; ж) $$7\frac{13}{14}$$; з) -0,64