计算:
(1) $(-3 \frac{3}{4})+4.25+(-3 \frac{1}{2})+12$；
(2) $(-0.5)+\frac{9}{2}+(-\frac{19}{2})+9.75$；
(3) $1 \frac{2}{3}+(-1 \frac{2}{5})+\frac{4}{3}+(-1)+(-3 \frac{3}{5})$；
(4) $6 \frac{4}{9}+(-2 \frac{1}{7})+(-2 \frac{2}{3})+\frac{15}{7}$；
(5) $14.5+(-2.5)+9 \frac{1}{3}+(-15 \frac{2}{3})+2 \frac{1}{3}$；
(6) $3 \frac{1}{5}+(-0.5)+\left|-3.2\right|+5 \frac{1}{2}$；
(7) $(+1.125)+(-3 \frac{3}{4})+\frac{1}{8}+(-0.25)$；
(8) $(-9 \frac{5}{12})+15 \frac{3}{4}+(-3 \frac{1}{4})+(-22 \frac{1}{2})+(-15 \frac{7}{12})$.

(1) 9
(2) 4.25
(3) -3
(4) $3\dfrac{7}{9}$
(5) 8
(6) $11\dfrac{2}{5}$
(7) $-2\dfrac{3}{4}$
(8) -35
【解析】原式$=(-9)+(-\dfrac{5}{12})+15+\dfrac{3}{4}+(-3)+(-\dfrac{1}{4})+(-22)+(-\dfrac{1}{2})+(-15)+(-\dfrac{7}{12})=(-9)+15+(-3)+(-22)+(-15)+(-\dfrac{5}{12})+\dfrac{3}{4}+(-\dfrac{1}{4})+(-\dfrac{1}{2})+(-\dfrac{7}{12})=(-34)+(-1)=-35.$