题目内容
(2011?巴中)计算下面各题,注意使用简便运算.
(1)
|
(2)
|
(3)(15-14×
| ||||||||||||||||||||||||
(4)
|
(5)
|
(6)
|
分析:(1)(2)把除法改为乘法,约分计算;
(3)先算括号内的乘法,再算括号内的减法,最后算括号外的乘法;
(4)运用乘法分配律简算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)先算除法,再运用加法结合律简算.
(3)先算括号内的乘法,再算括号内的减法,最后算括号外的乘法;
(4)运用乘法分配律简算;
(5)先算小括号内的,再算中括号内的,最后算括号外的;
(6)先算除法,再运用加法结合律简算.
解答:解:(1)
×
÷
,
=
×
×
,
=
;
(2)
÷
÷
,
=
×
×
,
=
;
(3)(15-14×
)×
,
=(15-8)×
,
=7×
,
=
;
(4)
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(5)
÷[(
+
)×
],
=
÷[
×
],
=
÷
,
=
×
,
=3;
(6)
-
-
÷
,
=
-
-
×
,
=
-
-
,
=
-(
+
),
=
-1,
=
.
4 |
9 |
1 |
5 |
4 |
5 |
=
4 |
9 |
1 |
5 |
5 |
4 |
=
1 |
9 |
(2)
4 |
5 |
2 |
3 |
5 |
6 |
=
4 |
5 |
3 |
2 |
6 |
5 |
=
36 |
25 |
(3)(15-14×
4 |
7 |
8 |
21 |
=(15-8)×
8 |
21 |
=7×
8 |
21 |
=
8 |
3 |
(4)
2 |
7 |
8 |
9 |
5 |
7 |
8 |
9 |
=(
2 |
7 |
5 |
7 |
8 |
9 |
=1×
8 |
9 |
=
8 |
9 |
(5)
4 |
5 |
1 |
3 |
2 |
5 |
4 |
11 |
=
4 |
5 |
11 |
15 |
4 |
11 |
=
4 |
5 |
4 |
15 |
=
4 |
5 |
15 |
4 |
=3;
(6)
7 |
5 |
5 |
8 |
9 |
16 |
3 |
2 |
=
7 |
5 |
5 |
8 |
9 |
16 |
2 |
3 |
=
7 |
5 |
5 |
8 |
3 |
8 |
=
7 |
5 |
5 |
8 |
3 |
8 |
=
7 |
5 |
=
2 |
5 |
点评:此题主要考查分数、整数、小数的四则混合运算的运算顺序和应用运算定律进行简便计算.
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