- a) $$17 + (-5) = 17 - 5 = 12$$.
- б) $$-21 + 19 = -2$$.
- в) $$-8 + (-43) = -8 - 43 = -51$$.
- г) $$-15 + (-18) = -15 - 18 = -33$$.
- д) $$-0,5 + 6 = 5,5$$.
- e) $$-2,4 + (-3,2) = -2,4 - 3,2 = -5,6$$.
- ж) $$6,1 + (-8,3) = 6,1 - 8,3 = -2,2$$.
- з) $$-3,84 + 4,16 = 0,32$$.
- и) $$\frac{-2}{9} + \frac{5}{9} = \frac{-2 + 5}{9} = \frac{3}{9} = \frac{1}{3}$$.
- к) $$\frac{-4}{7} + \frac{2}{7} = \frac{-4 + 2}{7} = \frac{-2}{7} = -\frac{2}{7}$$.
- л) $$\frac{5}{8} + (\frac{-7}{12}) = \frac{5}{8} - \frac{7}{12} = \frac{5 \times 3}{8 \times 3} - \frac{7 \times 2}{12 \times 2} = \frac{15}{24} - \frac{14}{24} = \frac{15 - 14}{24} = \frac{1}{24}$$.
- м) $$-1 + \frac{3}{5} = -\frac{5}{5} + \frac{3}{5} = \frac{-5 + 3}{5} = \frac{-2}{5} = -\frac{2}{5}$$.
- н) $$-2 + 1\frac{3}{4} = -2 + \frac{7}{4} = -\frac{8}{4} + \frac{7}{4} = \frac{-8 + 7}{4} = \frac{-1}{4} = -\frac{1}{4}$$.
- о) $$3 + (-\frac{12}{7}) = 3 - \frac{12}{7} = \frac{21}{7} - \frac{12}{7} = \frac{21 - 12}{7} = \frac{9}{7} = 1\frac{2}{7}$$.
- п) $$2\frac{2}{3} + (-1\frac{5}{6}) = \frac{8}{3} - \frac{11}{6} = \frac{8 \times 2}{3 \times 2} - \frac{11}{6} = \frac{16}{6} - \frac{11}{6} = \frac{16 - 11}{6} = \frac{5}{6}$$.
- р) $$-5\frac{1}{3} + 4,5 = -\frac{16}{3} + \frac{9}{2} = -\frac{16 \times 2}{3 \times 2} + \frac{9 \times 3}{2 \times 3} = -\frac{32}{6} + \frac{27}{6} = \frac{-32 + 27}{6} = \frac{-5}{6} = -\frac{5}{6}$$.
Ответ: a) 12; б) -2; в) -51; г) -33; д) 5,5; е) -5,6; ж) -2,2; з) 0,32; и) $$\frac{1}{3}$$; к) $$\frac{-2}{7}$$; л) $$\frac{1}{24}$$; м) $$\frac{-2}{5}$$; н) $$\frac{-1}{4}$$; о) $$1\frac{2}{7}$$; п) $$\frac{5}{6}$$; р) $$\frac{-5}{6}$$.