题目内容
计算:
(1)(-
)+(+
)
(2)|-7|+|-9
|
(3)(-4
)+(+3
)
(4)(-
)-(-3
)
(5)(-3.7)-
(6)
-
(7)(3-9)-(4-8)
(8)(-
)+(+
)+(+
)+(-1
)
(9)-(-3
)-(+
)-(-2
)
(10)(-36.35)+(-7.25)+26.35+(+7
)+10
(11)2
+(-2
)+(-1
)+4
+(-1
)+(-3
)
(12)|
-1|+|
-
|+|
-
|+|
-
|+…+|
-
|
(1)(-
| 1 |
| 3 |
| 1 |
| 2 |
(2)|-7|+|-9
| 7 |
| 15 |
(3)(-4
| 2 |
| 3 |
| 1 |
| 6 |
(4)(-
| 2 |
| 3 |
| 1 |
| 2 |
(5)(-3.7)-
| 3 |
| 10 |
(6)
| 1 |
| 3 |
| 1 |
| 4 |
(7)(3-9)-(4-8)
(8)(-
| 1 |
| 3 |
| 2 |
| 5 |
| 3 |
| 5 |
| 2 |
| 3 |
(9)-(-3
| 1 |
| 2 |
| 5 |
| 6 |
| 3 |
| 4 |
(10)(-36.35)+(-7.25)+26.35+(+7
| 1 |
| 4 |
(11)2
| 2 |
| 5 |
| 7 |
| 8 |
| 5 |
| 12 |
| 3 |
| 5 |
| 1 |
| 8 |
| 7 |
| 12 |
(12)|
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 3 |
| 1 |
| 5 |
| 1 |
| 4 |
| 1 |
| 2012 |
| 1 |
| 2011 |
分析:(1)根据有理数的加法法则通分后相加即可;
(2)去掉绝对值符号后相加即可;
(3)根据有理数的加法法则通分后相加即可;
(4)先化成加法,再根据有理数的加法法则进行计算即可;
(5)把分数变成小数,再相加即可;
(6)通分后相减即可;
(7)先算括号内的,再相减即可;
(8)把分母相同的相加,再进行加法求出即可;
(9)先把减法变成加法,再根据有理数的加法法则计算即可;
(10)把相加为整数和互为相反数的加数相加,再求出即可;
(11)把分母相同的相加,再进行加法求出即可;
(12)先去绝对值符号,再合并,最后计算求出即可.
(2)去掉绝对值符号后相加即可;
(3)根据有理数的加法法则通分后相加即可;
(4)先化成加法,再根据有理数的加法法则进行计算即可;
(5)把分数变成小数,再相加即可;
(6)通分后相减即可;
(7)先算括号内的,再相减即可;
(8)把分母相同的相加,再进行加法求出即可;
(9)先把减法变成加法,再根据有理数的加法法则计算即可;
(10)把相加为整数和互为相反数的加数相加,再求出即可;
(11)把分母相同的相加,再进行加法求出即可;
(12)先去绝对值符号,再合并,最后计算求出即可.
解答:解:(1)原式=
-
=
;
(2)原式=7+9
=16
;
(3)(-4
)+(+3
)
=-(4
-3
)
=-1
=-1
;
(4)(-
)-(-3
)
=(-
)+(+3
)
=3
-
=2
;
(5)(-3.7)-
=(-3.7)+(-0.3)
=-4;
(6)
-
=
-
=
;
(7)(3-9)-(4-8)
=-6-(-4)
=(-6)+(+4)
=-2;
(8)(-
)+(+
)+(+
)+(-1
)
=(-
)+(-1
)+(+
)+(+
)
=-2+1
=-1;
(9)-(-3
)-(+
)-(-2
)
=3
-
+2
=5
-
=5
-
=5
;
(10)(-36.35)+(-7.25)+26.35+(+7
)+10
=(-36.35)+26.35+(-7.25)+(+7.25)+10
=-10+10
=0;
(11)2
+(-2
)+(-1
)+4
+(-1
)+(-3
)
=2
+4
+(-2
)+(-1
)+(-1
)+(-3
)
=7-4-5
=-2;
(12)|
-1|+|
-
|+|
-
|+|
-
|+…|
-
|
=1-
+
-
+
-
+…+
-
=1-
=
.
| 1 |
| 2 |
| 1 |
| 3 |
=
| 1 |
| 6 |
(2)原式=7+9
| 7 |
| 15 |
=16
| 7 |
| 15 |
(3)(-4
| 2 |
| 3 |
| 1 |
| 6 |
=-(4
| 2 |
| 3 |
| 1 |
| 6 |
=-1
| 3 |
| 6 |
=-1
| 1 |
| 2 |
(4)(-
| 2 |
| 3 |
| 1 |
| 2 |
=(-
| 2 |
| 3 |
| 1 |
| 2 |
=3
| 1 |
| 2 |
| 2 |
| 3 |
=2
| 5 |
| 6 |
(5)(-3.7)-
| 3 |
| 10 |
=(-3.7)+(-0.3)
=-4;
(6)
| 1 |
| 3 |
| 1 |
| 4 |
=
| 4 |
| 12 |
| 3 |
| 12 |
=
| 1 |
| 12 |
(7)(3-9)-(4-8)
=-6-(-4)
=(-6)+(+4)
=-2;
(8)(-
| 1 |
| 3 |
| 2 |
| 5 |
| 3 |
| 5 |
| 2 |
| 3 |
=(-
| 1 |
| 3 |
| 2 |
| 3 |
| 2 |
| 5 |
| 3 |
| 5 |
=-2+1
=-1;
(9)-(-3
| 1 |
| 2 |
| 5 |
| 6 |
| 3 |
| 4 |
=3
| 1 |
| 2 |
| 5 |
| 6 |
| 3 |
| 4 |
=5
| 5 |
| 4 |
| 5 |
| 6 |
=5
| 15 |
| 12 |
| 10 |
| 12 |
=5
| 5 |
| 12 |
(10)(-36.35)+(-7.25)+26.35+(+7
| 1 |
| 4 |
=(-36.35)+26.35+(-7.25)+(+7.25)+10
=-10+10
=0;
(11)2
| 2 |
| 5 |
| 7 |
| 8 |
| 5 |
| 12 |
| 3 |
| 5 |
| 1 |
| 8 |
| 7 |
| 12 |
=2
| 2 |
| 5 |
| 3 |
| 5 |
| 7 |
| 8 |
| 1 |
| 8 |
| 5 |
| 12 |
| 7 |
| 12 |
=7-4-5
=-2;
(12)|
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 2 |
| 1 |
| 4 |
| 1 |
| 3 |
| 1 |
| 5 |
| 1 |
| 4 |
| 1 |
| 2012 |
| 1 |
| 2011 |
=1-
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 3 |
| 1 |
| 4 |
| 1 |
| 2011 |
| 1 |
| 2012 |
=1-
| 1 |
| 2012 |
=
| 2011 |
| 2012 |
点评:本题考查了有理数的加减混合运算,主要考查学生的计算能力.
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