试题

题目:
(1)(-100)+100
(2)(-35)+0
(3)(-0.5)+4.4
(4)(-16)+(-8)
(5)(-4.2)+4.25
(6)0-(+52)
(7)(-14)-(-15)
(8)(-1.24)-(+4.76)
(9)(-6)×0
(10)(-0.5)×(-8)
(11)(
1
4
-
1
2
+
1
6
)×12

(12)100×(-1)×(-0.1)
(13)(-
1
2
)-(-3
1
4
)+(+2
3
4
)-(+5
1
2
)

(14)|-2
1
4
|-(-
3
4
)+1-|1-
1
2
|

(15)1-(-1)(-1)-(-1)×0
(16)-4.2+5.7-7.6+10.1-5.5
(17)25×
3
4
-25×
1
2
-25×(-
1
4
)

(18)(-5)-(-25)×
1
5
×(-4)+(-6)×
1
2

答案
解:(1)原式=7;

(右)原式=-3左;

(3)原式=4.4-7.左
=3.9;

(4)原式=-右4;

(左)原式=7.7左;

(6)原式=-左右;

(7)原式=-14+1左
=1;

(8)原式=-1.右4-4.76
=-6;

(9)原式=7;

(17)原式=4;

(11)原式=
1
4
×1右-
1
×1右+
1
6
×1右
=3-6+右=左-6
=-1;

(1右)原式=17;

(13)原式=-
1
+3
1
4
+右
3
4
-左
1

=-6+6
=7;

(14)原式=右
1
4
+
3
4
+1-
1

=3+
1

=3
1


(1左)原式=1-1-7
=7;

(16)原式=-4.右-左.左+左.7-7.6+17.1
=-9.7+左.7+右.左
=-4+右.左
=-1.左;

(17)原式=右左(
3
4
-
1
+
1
4

=右左×
1

=1右.左;

(18)原式=-左-右7-3
=-右8.
解:(1)原式=7;

(右)原式=-3左;

(3)原式=4.4-7.左
=3.9;

(4)原式=-右4;

(左)原式=7.7左;

(6)原式=-左右;

(7)原式=-14+1左
=1;

(8)原式=-1.右4-4.76
=-6;

(9)原式=7;

(17)原式=4;

(11)原式=
1
4
×1右-
1
×1右+
1
6
×1右
=3-6+右=左-6
=-1;

(1右)原式=17;

(13)原式=-
1
+3
1
4
+右
3
4
-左
1

=-6+6
=7;

(14)原式=右
1
4
+
3
4
+1-
1

=3+
1

=3
1


(1左)原式=1-1-7
=7;

(16)原式=-4.右-左.左+左.7-7.6+17.1
=-9.7+左.7+右.左
=-4+右.左
=-1.左;

(17)原式=右左(
3
4
-
1
+
1
4

=右左×
1

=1右.左;

(18)原式=-左-右7-3
=-右8.
考点梳理
有理数的混合运算.
(1)到(6)利用有理数加法法运算;
(7)、(8)先去括号,再进行有理数加法运算;
(9)、(10)、(12)根据有理数乘法法则运算;
(11)、(17)利用乘法的分配律进行运算;
(13)、(14)先进行同分母的加减运算;
(15)、(18)先进行乘法运算,再进行加减运算;
(16)先计算-4.2-5.5和-7.6+10.1,然后进行加减运算.
本题考查了有理数混合运算:先算乘方,再算乘除,最后算加减;同级运算,应按从左到右的顺序进行计算;如果有括号,要先做括号内的运算.
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