1) -\frac{8}{15}+\frac{2}{15}= 2) 28+\left(-\frac{19}{31}\right)= 5)-6\frac{2}{19}+21= 6) 23+\left(-5\frac{7}{18}\right)= 3) -\frac{16}{17}+\left(-\frac{13}{17}\right)= 4) -4\frac{16}{22}+\left(-\frac{3}{22}\right)= 7) 5+\left(-2\frac{6}{25}\right)= 8) -13\frac{15}{18}+\left(-\frac{11}{18}\right)=

3 уровень. Вычислите

1. $$\frac{-8}{15} + \frac{2}{15} = \frac{-8+2}{15} = \frac{-6}{15} = -\frac{2}{5}$$
2. $$28 + (-\frac{19}{31}) = \frac{28 \cdot 31}{31} - \frac{19}{31} = \frac{868 - 19}{31} = \frac{849}{31} = 27\frac{12}{31}$$
3. $$-\frac{16}{17} + (-\frac{13}{17}) = \frac{-16-13}{17} = \frac{-29}{17} = -1\frac{12}{17}$$
4. $$-4\frac{16}{22} + (-\frac{3}{22}) = -4 \frac{16+3}{22} = -4\frac{19}{22}$$
5. $$-6\frac{2}{19}+21 = 21 - 6\frac{2}{19} = 14\frac{17}{19}$$
6. $$23 + (-5\frac{7}{18}) = 23 - 5\frac{7}{18} = 17\frac{11}{18}$$
7. $$5 + (-2\frac{6}{25}) = 5 - 2\frac{6}{25} = 2\frac{19}{25}$$
8. $$-13\frac{15}{18} + (-\frac{11}{18}) = -13 \frac{15+11}{18} = -13 \frac{26}{18} = -13 - 1\frac{8}{18} = -14\frac{4}{9}$$

Ответ: 1) $$\frac{-2}{5}$$; 2) $$27\frac{12}{31}$$; 3) $$-1\frac{12}{17}$$; 4) $$-4\frac{19}{22}$$; 5) $$14\frac{17}{19}$$; 6) $$17\frac{11}{18}$$; 7) $$2\frac{19}{25}$$; 8) $$-14\frac{4}{9}$$