试题

题目:
计算:
(1)(-3)+(-4)-(+11)-(-9);
(2)-5
3
4
-[-1.5-(4.5-4
3
4
)]

(3)(
2
3
-
1
12
-
1
15
)×(-60)

(4)(-81)÷
9
4
×
4
9
÷(-16)

(5)-14÷(-52)×(-
5
3
)+|0.8-1|

(6)
1
4
×(-23
4
5
-(-8)÷[(-0.2)2-(-0.96) ] 

答案
解:(1)(-3)+(-4)-(+11)-(-9)=-3-4-11+9=-18+9=-9;
(2)-5
3
4
-[-1.5-(4.5-4
3
4
)]
=-5
3
4
-(-1.5-4.5+4
3
4
)
=-5
3
4
+1.5+4.5-4
3
4
=-
39
4
+6=-
15
4

(3)(
2
3
-
1
12
-
1
15
)×(-60)
=
2
3
×(-60)-
1
12
×(-60)-
1
15
×(-60)
=-40+5+4=-31;
(4)(-81)÷
9
4
×
4
9
÷(-16)
=81×
4
9
×
4
9
×
1
16
=1;
(5)-14÷(-52)×(-
5
3
)+|0.8-1|
=-1×(-
1
25
)×(-
5
3
)
+0.2=-
1
15
+
1
5
=
2
15

(6)
1
4
×(-23
4
5
-(-8)÷[(-0.2)2-(-0.96) ] 
=
1
4
×(-8)×(
5
4
)
-(-8)÷(0.04+0.96)=-2.25-(-8)=5.75.
解:(1)(-3)+(-4)-(+11)-(-9)=-3-4-11+9=-18+9=-9;
(2)-5
3
4
-[-1.5-(4.5-4
3
4
)]
=-5
3
4
-(-1.5-4.5+4
3
4
)
=-5
3
4
+1.5+4.5-4
3
4
=-
39
4
+6=-
15
4

(3)(
2
3
-
1
12
-
1
15
)×(-60)
=
2
3
×(-60)-
1
12
×(-60)-
1
15
×(-60)
=-40+5+4=-31;
(4)(-81)÷
9
4
×
4
9
÷(-16)
=81×
4
9
×
4
9
×
1
16
=1;
(5)-14÷(-52)×(-
5
3
)+|0.8-1|
=-1×(-
1
25
)×(-
5
3
)
+0.2=-
1
15
+
1
5
=
2
15

(6)
1
4
×(-23
4
5
-(-8)÷[(-0.2)2-(-0.96) ] 
=
1
4
×(-8)×(
5
4
)
-(-8)÷(0.04+0.96)=-2.25-(-8)=5.75.
考点梳理
有理数的混合运算.
(1)先简化符号,再结合同号数计算;
(2)先去小括号,再去中括号计算;
(3)按乘法分配律计算;
(4)先确定符号,把除法转化为乘法,再约分计算;
(5)(6)先乘方,后乘除,有括号先算括号里的.
本题考查的是有理数的混合运算的能力,要注意运算顺序及符号的处理,灵活应用运算律可使计算简便.
找相似题