问题 解答题
计算:
(1)(+2)+(-11);
(2)(+20)+(+12);
(3)(-1
1
2
)+(-
2
3
);
(4)(-3.4)+4.3.
答案

(1)(+2)+(-11)=2-11=-9;

(2)(+20)+(+12)=20+12=32;

(3)(-1

1
2
)+(-
2
3
)=-1
1
2
-
2
3
=-2
1
6

(4)(-3.4)+4.3=-3.4+4.3=0.9.

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