题目内容
(2012?哈尔滨模拟)计算,能简算的要简算
÷
+
+
×
+
×
[1-(
-
)]×
(
+
)×23+
.
| 1 |
| 3 |
| 4 |
| 9 |
| 1 |
| 3 |
| 1 |
| 4 |
| 2 |
| 5 |
| 18 |
| 5 |
| 3 |
| 5 |
| 18 |
| 5 |
[1-(
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 5 |
(
| 1 |
| 69 |
| 2 |
| 71 |
| 25 |
| 71 |
分析:(1)先算除法,再运用加法交换律简算;
(2)运用乘法分配律简算;
(3)先算小括号里面的减法,再算中括号里面的减法,最后算括号外的乘法;
(4)先运用乘法分配律简算,再运用加法结合律简算.
(2)运用乘法分配律简算;
(3)先算小括号里面的减法,再算中括号里面的减法,最后算括号外的乘法;
(4)先运用乘法分配律简算,再运用加法结合律简算.
解答:解:(1)
÷
+
+
,
=
+
+
,
=
+
+
,
=1+
,
=1
;
(2)
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(3)[1-(
-
)]×
,
=[1-
]×
,
=
×
,
=
;
(4)(
+
)×23+
,
=
×23+
×23+
,
=
+
+
,
=
+(
+
),
=
+1,
=1
.
| 1 |
| 3 |
| 4 |
| 9 |
| 1 |
| 3 |
| 1 |
| 4 |
=
| 3 |
| 4 |
| 1 |
| 3 |
| 1 |
| 4 |
=
| 3 |
| 4 |
| 1 |
| 4 |
| 1 |
| 3 |
=1+
| 1 |
| 3 |
=1
| 1 |
| 3 |
(2)
| 2 |
| 5 |
| 18 |
| 5 |
| 3 |
| 5 |
| 18 |
| 5 |
=(
| 2 |
| 5 |
| 3 |
| 5 |
| 18 |
| 5 |
=1×
| 18 |
| 5 |
=
| 18 |
| 5 |
(3)[1-(
| 1 |
| 2 |
| 1 |
| 3 |
| 1 |
| 5 |
=[1-
| 1 |
| 6 |
| 1 |
| 5 |
=
| 5 |
| 6 |
| 1 |
| 5 |
=
| 1 |
| 6 |
(4)(
| 1 |
| 69 |
| 2 |
| 71 |
| 25 |
| 71 |
=
| 1 |
| 69 |
| 2 |
| 71 |
| 25 |
| 71 |
=
| 1 |
| 3 |
| 46 |
| 71 |
| 25 |
| 71 |
=
| 1 |
| 3 |
| 46 |
| 71 |
| 25 |
| 71 |
=
| 1 |
| 3 |
=1
| 1 |
| 3 |
点评:运算定律是常用的简便运算的方法,要熟练掌握,灵活运用.
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