(1)$(+89.9)+(-100)=$；(2)$(-1.8)+(-3.2)=$；

(1)-10.1 (2)-5

(3)$2\dfrac{7}{11} + (-1\dfrac{3}{11}) = \_\_\_\_\_\_;$
(4)$(-0.125) + (+\dfrac{1}{8}) = \_\_\_\_\_\_;$

(3)$1\dfrac{4}{11}$ (4)0

2. 计算:
(1)$(-12)+13+(-5.5)$;
(2)$-(-10)+0+(-6)$;
(3)$(-\dfrac{22}{5})+(-2\dfrac{1}{10})+(17\dfrac{4}{5})$;
(4)$(-3.75)+\dfrac{17}{3}+(-2\dfrac{3}{4})$;
(5)$15+(-20)+28+(-10)+(-15)$;
(6)$(-7.9)+4.3+2.9+(-1.3)$;
(7)$-\dfrac{2}{3}+\dfrac{1}{2}+(-\dfrac{1}{4})+\dfrac{1}{5}$;
(8)$\left|-\dfrac{1}{2}\right|+4\dfrac{1}{6}+(-5.25)+(-2\dfrac{2}{5})$.

(1)-4.5 (2)4 (3)11.3 (4)$-\dfrac{5}{6}$ (5)-2 (6)-2 (7)$-\dfrac{13}{60}$ (8)$-2\dfrac{59}{60}$