试题

题目:
计算
(1)-3-4+19-11+2
(2)3×(-4)+(-28)÷7
(3)(
1
2
-
5
6
-
2
9
)×36

(4)1
2
3
×(-
4
9
)×(-2.5)÷(-
25
3
)

(5)|-1
1
5
|÷(
1
3
-
1
5
)-
1
3
×(-3)2

(6)1-
1
2
×[3×(-
2
3
)2-(-1)4]+
1
4
÷(-
1
2
)3

答案
解:(1)-3-4+19-11+2,
=(-3-4-11)+(19+2),
=-(3+4+11)+(19+2),
=-18+21,
=3;

(2)3×(-4)+(-28)÷7,
=-12+(-4),
=-16;

(3)(
1
2
-
5
6
-
2
9
)×36,
=
1
2
×36-
5
6
×36-
2
9
×36,
=18-30-8,
=18-38,
=-20;

(4)1
2
3
×(-
4
9
)×(-2.5)÷(-
25
3
),
=
5
3
×(-
4
9
)×(-
5
2
)×(-
3
25
),
=-
5
3
×
4
9
×
5
2
×
3
25

=-
2
9


(5)|-1
1
5
|÷(
1
3
-
1
5
)-
1
3
×(-3)2
=|-
6
5
2
15
-
1
3
×9,
=
6
5
×
15
2
-3,
=9-3,
=6;

(6)1-
1
2
×[3×(-
2
3
2-(-1)4]+
1
4
÷(-
1
2
3
=1-
1
2
×(3×
4
9
-1)+
1
4
÷(-
1
8
),
=1-
1
2
×(
4
3
-1)+
1
4
×(-8),
=1-
1
2
×
1
3
-2,
=1-
1
6
-2,
=-
7
6

解:(1)-3-4+19-11+2,
=(-3-4-11)+(19+2),
=-(3+4+11)+(19+2),
=-18+21,
=3;

(2)3×(-4)+(-28)÷7,
=-12+(-4),
=-16;

(3)(
1
2
-
5
6
-
2
9
)×36,
=
1
2
×36-
5
6
×36-
2
9
×36,
=18-30-8,
=18-38,
=-20;

(4)1
2
3
×(-
4
9
)×(-2.5)÷(-
25
3
),
=
5
3
×(-
4
9
)×(-
5
2
)×(-
3
25
),
=-
5
3
×
4
9
×
5
2
×
3
25

=-
2
9


(5)|-1
1
5
|÷(
1
3
-
1
5
)-
1
3
×(-3)2
=|-
6
5
2
15
-
1
3
×9,
=
6
5
×
15
2
-3,
=9-3,
=6;

(6)1-
1
2
×[3×(-
2
3
2-(-1)4]+
1
4
÷(-
1
2
3
=1-
1
2
×(3×
4
9
-1)+
1
4
÷(-
1
8
),
=1-
1
2
×(
4
3
-1)+
1
4
×(-8),
=1-
1
2
×
1
3
-2,
=1-
1
6
-2,
=-
7
6
考点梳理
有理数的混合运算.
(1)根据有理数的加减混合运算顺序进行运算即可;
(2)先算乘除,再算加减即可;
(3)根据乘法分配律进行计算;
(4)把带分数与小数都化为假分数,除法转化为乘法运算,然后进行计算即可求解;
(5)去掉绝对值号,然后先算除法与乘方运算,再算减法运算即可;
(6)根据有理数的混合运算顺序,先算乘方,再算乘除,最后算加减,有括号的先算括号里面的,进行计算即可.
本题考查的是有理数的运算能力.注意:要正确掌握运算顺序,在混合运算中要特别注意运算顺序:先三级,后二级,再一级;有括号的先算括号里面的;同级运算按从左到右的顺序.
计算题.
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