问题 解答题
(1)(-19)-(+42)-(-5)+(-9)
(2)(-5)×(-7)-5×(-6)
(3)(
5
12
+
2
3
-
3
4
)×(-12)

(4)(-3)2-23÷
1
3
×3
答案

(1)原式=-19-42+5-9

=-70+5

=-65;

(2)原式=25+30

=65;

(3)原式=-12×

5
12
-12×
2
3
+12×
3
4

=-5-8+9

=-4;

(4)原式=9-8×3×3

=9-72

=-63.

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