4.221 Выполните сложение: д) -4 +27 8 ж)8+(−7): 2 7 5 14 e) 10+(-8): 5 13 3)-9/+8,5.

д) $$-4 + 2\frac{7}{8} = -4 + \frac{2 \cdot 8 + 7}{8} = -4 + \frac{23}{8} = - \frac{32}{8} + \frac{23}{8} = \frac{-32 + 23}{8} = \frac{-9}{8} = -1\frac{1}{8}$$

Ответ: $$-1\frac{1}{8}$$

е) $$10 + (-8\frac{5}{13}) = 10 - 8\frac{5}{13} = 10 - \frac{8 \cdot 13 + 5}{13} = 10 - \frac{109}{13} = \frac{130}{13} - \frac{109}{13} = \frac{130 - 109}{13} = \frac{21}{13} = 1\frac{8}{13}$$

Ответ: $$1\frac{8}{13}$$

ж) $$8\frac{2}{7} + (-\frac{7}{14}) = \frac{8 \cdot 7 + 2}{7} - \frac{7}{14} = \frac{58}{7} - \frac{7}{14} = \frac{58 \cdot 2 - 7}{14} = \frac{116 - 7}{14} = \frac{109}{14} = 7\frac{11}{14}$$

Ответ: $$7\frac{11}{14}$$

з) $$-9\frac{1}{7} + 8,5 = - \frac{9 \cdot 7 + 1}{7} + 8,5 = - \frac{64}{7} + 8,5 = - \frac{64}{7} + \frac{85}{10} = - \frac{64}{7} + \frac{17}{2} = \frac{-64 \cdot 2 + 17 \cdot 7}{14} = \frac{-128 + 119}{14} = \frac{-9}{14}$$

Ответ: $$\frac{-9}{14}$$