问题 解答题
计算:
(1)
5
2
-
7
10
×30+8
1
2

(2)28×
3
4
-(-28)×0.5+28×(-
1
4
)

(3)(-1)+(1-
1
2
)÷3×(2-23)
答案

(1)原式=2.5-21+8.5=-10;

(2)原式=28×(

3
4
+0.5-
1
4
)=28;

(3)原式=-1+0.5÷3×(2-8)

=-1+0.5÷3×(-6)

=-1-1

=-2

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