问题 解答题
计算
(1)(-4)-(+8)-(-5)+(-9);
(2)(-5)×(-7)-5×(-6)
(3)(-9)÷
3
2
×
2
3
÷(-4)

(4)(1-
1
2
-
1
3
)×(-12)

(5)3+50÷(-2)2×(-
1
5
)-1
答案

(1)原式=-4-8+5-9

=-12+5-9

=-7-9

=-16;

(2)原式=35+30

=65;

(3)原式=(-9)×

2
3
×
2
3
×(-
1
4

=(-6)×

2
3
×(-
1
4

=(-4)×(-

1
4

=1;

(4)原式=1×(-12)-

1
2
×(-12)-
1
3
×(-12)

=-12+6+4

=-2;

(5)原式=3+50÷4×(-

1
5
)-1

=3+50×

1
4
×(-
1
5
)-1

=3+

25
2
×(-
1
5
)-1

=3-

5
2
-1

=-

1
2

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