6.16 Вычислите: a) 7$$\frac{5}{11}$$+5$$\frac{8}{11}$$-2$$\frac{2}{11}$$+2$$\frac{8}{11}$$; б) 9$$\frac{6}{15}$$-5$$\frac{3}{5}$$+4$$\frac{4}{15}$$+2$$\frac{2}{5}$$.

Решение:

а) 7$$\frac{5}{11}$$+5$$\frac{8}{11}$$-2$$\frac{2}{11}$$+2$$\frac{8}{11}$$ = (7+5-2+2) + ($$\frac{5}{11}$$+$$\frac{8}{11}$$-$$\frac{2}{11}$$+$$\frac{8}{11}$$) = 12 + $$\frac{5+8-2+8}{11}$$ = 12 + $$\frac{19}{11}$$ = 12 + 1$$\frac{8}{11}$$ = 13$$\frac{8}{11}$$.

б) 9$$\frac{6}{15}$$-5$$\frac{3}{5}$$+4$$\frac{4}{15}$$+2$$\frac{2}{5}$$ = 9$$\frac{6}{15}$$-5$$\frac{9}{15}$$+4$$\frac{4}{15}$$+2$$\frac{6}{15}$$ = (9-5+4+2) + ($$\frac{6}{15}$$-$$\frac{9}{15}$$+$$\frac{4}{15}$$+$$\frac{6}{15}$$) = 10 + $$\frac{6-9+4+6}{15}$$ = 10 + $$\frac{7}{15}$$ = 10$$\frac{7}{15}$$.

Ответ: а) 13$$\frac{8}{11}$$; б) 10$$\frac{7}{15}$$