题目内容

计算:
(1)23+(-58);
(2)(-2)2×(-5);
(3)13-17-(-7);
(4)-2-5+23-9+7;
(5)-(-3)+|-3|-(-3)2
(6)(-2)÷
1
3
×(-3)

(7)(-3)2×23-(-4)÷2;
(8)12×(
2
3
-
1
6
);
(9)-14+8÷(-2)2-(-4)×(-3);
(10)0÷(-5)-53-5;
(11)19
24
25
×(-25)

(12)25×
3
4
-(-25)×
1
2
+25×(-
1
4
)
分析:(1)按照异号两数的加法运算法则进行运算即可;
(2)先算乘方,再算乘法;
(3)先去括号,然后按照有理数的加法的运算法则进行运算即可;
(4)直接按照有理数的加法进行计算即可;
(5)先算出乘方和绝对值,然后进行有理数的加法即可;
(6)按照从左到右的顺序依次进行运算即可;
(7)先算乘方,再算乘除,最后算加减;
(8)按照分配律展开计算即可;
(9)先算乘方,后算乘除,最后算加减即可;
(10)先算乘方,后算乘除,最后算加减即可;
 (11)将原式转化为(20-
1
25
)×(-25)后按照分配律进行展开运算即可;
 (12)逆用分配律展开即可.
解答:解:(1)23+(-58)
=-(58-23)
=-35;
(2)(-2)2×(-5)
=4×(-5)
=-20;
(3)13-17-(-7)
=13-17+7
=3;
(4)-2-5+23-9+7
=-2-5-9+23+7
=14;
(5)-(-3)+|-3|-(-3)2
=3+3-9
=-3
(6)(-2)÷
1
3
×(-3)

=-2×3×(-3)
=18;
(7)(-3)2×23-(-4)÷2
=9×8-(-2)
=74;
(8)12×(
2
3
-
1
6

=12×
2
3
-12×
1
6

=8-2
=6;
(9)-14+8÷(-2)2-(-4)×(-3)
=-1+2-12
=-11;
(10)0÷(-5)-53-5
=0-125-5
=-130;
(11)19
24
25
×(-25)

=(20-
1
25
)×(-25)
=-20×25+
1
25
×25
=-499;
(12)25×
3
4
-(-25)×
1
2
+25×(-
1
4
)

=25×(
3
4
+
1
2
-
1
4

=25.
点评:本题考查了有理数的混合运算,牢记法则并认真的计算是解决此类题目的关键.
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