题目内容
计算:(1)(+1 |
4 |
1 |
3 |
3 |
4 |
2 |
3 |
(2)-24+3-16-5;
(3)-23÷
4 |
9 |
2 |
3 |
(4)
3 |
4 |
1 |
3 |
14 |
15 |
(5)(-5
1 |
2 |
4 |
11 |
(6)(
2 |
9 |
1 |
4 |
1 |
18 |
1 |
36 |
(7)-32×
1 |
3 |
3 |
5 |
1 |
4 |
(8)(
1 |
2 |
1 |
3 |
5 |
6 |
9 |
14 |
5 |
9 |
(9)-14-(1-0.5)×
1 |
3 |
(10)-32-|(-5)3|×(-
2 |
5 |
(11)-14-(-5
1 |
2 |
4 |
11 |
(12)(-47.65)×2
6 |
11 |
6 |
11 |
5 |
11 |
分析:(1)(2)(5)(8)可直接按照有理数的混合运算进行;
(3)(7)(9)(10)(11)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;
(4)(6)可利用分配律计算;
(12)可利用结合律进行运算,最后得出结果.
(3)(7)(9)(10)(11)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;
(4)(6)可利用分配律计算;
(12)可利用结合律进行运算,最后得出结果.
解答:解:(1)原式=
-
+
-
=
-
=3-6=-3;
(2)原式=-21-16-5=-37-5=-42;
(3)原式=-8×
×
=-8;
(4)原式=
×8-
×
-
×
=6-1-
=
;
(5)原式=-
×
-8÷2=-2-4=-6;
(6)原式=
×(-36)-
×(-36)+
×(-36)=-8+9-2=1-2=-1;
(7)原式=-9×
-[25×(-
)-240×(-
)×
-2]
=-3-(-15+15-2)=-3+2=-1;
(8)原式=
×(-
)-
×(-
)=-1+1=0;
(9)原式=-1-
×
×(2-9)=-1-
×(-7)=-1+
=
;
(10)原式=-9-125×
-18÷9=-9-20-2=-31;
(11)原式=-1-(-
)×
-8=-1+2-8=-7;
(12)原式=(37.15-47.65)×2
-10.5×7
=-10.5×
-10.5×
=-10.5×(
+
)
=-10.5×10
=-105.
1 |
4 |
7 |
3 |
11 |
4 |
11 |
3 |
12 |
4 |
18 |
3 |
(2)原式=-21-16-5=-37-5=-42;
(3)原式=-8×
9 |
4 |
4 |
9 |
(4)原式=
3 |
4 |
3 |
4 |
4 |
3 |
3 |
4 |
14 |
15 |
7 |
10 |
43 |
10 |
(5)原式=-
11 |
2 |
4 |
11 |
(6)原式=
2 |
9 |
1 |
4 |
1 |
18 |
(7)原式=-9×
1 |
3 |
3 |
5 |
1 |
4 |
1 |
4 |
=-3-(-15+15-2)=-3+2=-1;
(8)原式=
5 |
6 |
6 |
5 |
9 |
14 |
14 |
9 |
(9)原式=-1-
1 |
2 |
1 |
3 |
1 |
6 |
7 |
6 |
1 |
6 |
(10)原式=-9-125×
4 |
25 |
(11)原式=-1-(-
11 |
2 |
4 |
11 |
(12)原式=(37.15-47.65)×2
6 |
11 |
5 |
11 |
=-10.5×
28 |
11 |
82 |
11 |
=-10.5×(
28 |
11 |
82 |
11 |
=-10.5×10
=-105.
点评:本题考查的是有理数的运算.注意:要正确掌握运算顺序,即乘方运算(和以后学习的开方运算)叫做三级运算;乘法和除法叫做二级运算;加法和减法叫做一级运算.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.
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