题目内容

计算:
(1)(-
6
5
)-(+0.2)+1                       (2)(-2.25)+(-5.1)+
1
4
-(-4
1
8
)+(-
9
10

(3)(-48)÷(+
7
4
)÷(-12)×
7
4
              (4)-3
3
4
÷(-5)×(-
1
5
)÷
3
10

(5)-(-14)+(-2)2-(-3)3-23               (6)-12+(-
1
2
-
2
3
+
3
4
)×(-24)
(7)-19
15
16
×16                               (8)(-15)÷(+
7
2
)-(-12)×
2
7
-(+11)÷
7
2
考点:有理数的混合运算
专题:
分析:(1)(2)先化简,再分类计算;
(3)(4)先判定符号,再按照从左到右的顺序计算;
(5)先算乘方,再算加减;
(6)(7)(8)利用乘法分配律简算.
解答:解:(1)(-
6
5
)-(+0.2)+1
=-
6
5
-0.2+1
=-0.4;
(2)(-2.25)+(-5.1)+
1
4
-(-4
1
8
)+(-
9
10

=-2.25-5.1+
1
4
+4
1
8
-
9
10

=-3
7
8

(3)(-48)÷(+
7
4
)÷(-12)×
7
4
 
=48÷
7
4
÷12×
7
4

=4;     
(4)-3
3
4
÷(-5)×(-
1
5
)÷
3
10

=-
15
4
×
1
5
×
1
5
×
10
3

=-
1
2

(5)-(-14)+(-2)2-(-3)3-23 
=1+4+27-8
=24;
(6)-12+(-
1
2
-
2
3
+
3
4
)×(-24)
=-1-
1
2
×(-24)-
2
3
×(-24)+
3
4
×(-24)
=-1+12+16-18
=9;
(7)-19
15
16
×16
=-20×16+
1
16
×16
=-320+1
=-319;
(8)(-15)÷(+
7
2
)-(-12)×
2
7
-(+11)÷
7
2

=-15×
2
7
+12×
2
7
-11×
2
7

=(-15+12-11)×
2
7

=-14×
2
7

=-4.
点评:此题考查有理数的混合运算,掌握运算顺序,正确判定符号计算即可.
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