试题

题目:
计算 
(1)(-3.6)+(+得.5)
(得)3-得×(-5)
(3)-得4×(-
5
6
+
3
8
-
1
1得
)

(4)
1
+(-
3
)+
4
5
+(-
1
)+(-
1
3
)

(5)-14-(
13
14
-
11
1得
)×[4-(-得)]

(6)5×(-6)-(-4)÷(-8)
(o)-o.得-大.9-5.6+1.o
(8)(-1
3
5
)+(-3.得)+|-1.8|

答案
解:(1)(-3.6)+(+2.5)=-1.1;

(2)3-2×(-5)2
=3-2×25
=3-50
=-47;

(3)-24×(-
5
6
+
3
8
-
1
12
)

=24×
5
6
-24×
3
8
+24×
1
12

=20-9+2
=13;

(4)
1
2
+(-
2
3
)+
4
5
+(-
1
2
)+(-
1
3
)

=(
1
2
-
1
2
)+(-
2
3
-
1
3
)+
4
5

=0-1+
4
5

=-
1
5


(5)-14-(
13
14
-
11
12
)×[4-(-2)2]

=-1-(
13
14
-
11
12
)×[4-4]
=-1-(
13
14
-
11
12
)×0
=-1-0
=-1;

(6)5×(-6)-(-4)2÷(-8)
=-30-16÷(-8)
=-30+2
=-28;

(7)-7.2-0.9-5.6+1.7
=-13.7+1.7
=-12;

(8)(-1
3
5
)+(-3.2)+|-1.8|

=-1.6-3.2+1.8
=-4.8+1.8
=-3.
解:(1)(-3.6)+(+2.5)=-1.1;

(2)3-2×(-5)2
=3-2×25
=3-50
=-47;

(3)-24×(-
5
6
+
3
8
-
1
12
)

=24×
5
6
-24×
3
8
+24×
1
12

=20-9+2
=13;

(4)
1
2
+(-
2
3
)+
4
5
+(-
1
2
)+(-
1
3
)

=(
1
2
-
1
2
)+(-
2
3
-
1
3
)+
4
5

=0-1+
4
5

=-
1
5


(5)-14-(
13
14
-
11
12
)×[4-(-2)2]

=-1-(
13
14
-
11
12
)×[4-4]
=-1-(
13
14
-
11
12
)×0
=-1-0
=-1;

(6)5×(-6)-(-4)2÷(-8)
=-30-16÷(-8)
=-30+2
=-28;

(7)-7.2-0.9-5.6+1.7
=-13.7+1.7
=-12;

(8)(-1
3
5
)+(-3.2)+|-1.8|

=-1.6-3.2+1.8
=-4.8+1.8
=-3.
考点梳理
有理数的混合运算.
(1)根据有理数的加法法则计算即可;
(2)(5)(6)按照有理数混合运算的顺序,先乘方后乘除最后算加减,有括号的先算括号里面的;
(3)直接运用乘法的分配律计算;
(4)先算同分母分数,再相加即可;
(7)先算同号的数,再算异号的数;
(8)先算绝对值,再进行加减运算即可求解.
本题考查的是有理数的运算能力.注意:
(1)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;
(2)去括号法则:--得+,-+得-,++得+,+-得-.
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