题目内容
怎样简便怎样计算.
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(
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34-34×
|
[4-(
|
|
分析:(1)(3)约分计算;
(2)(4)(7)运用乘法分配律简算;
(5)此题不能用乘法分配律简算,可先算乘法,再算加法;
(6)中括号内运用减法的性质以及加法交换律与结合律,最后算括号外的乘法;
(8)先算小括号内的,再算中括号内的,最后算括号外的;
(9)先算括号内的,再算括号外的乘法,最后算加法.
(2)(4)(7)运用乘法分配律简算;
(5)此题不能用乘法分配律简算,可先算乘法,再算加法;
(6)中括号内运用减法的性质以及加法交换律与结合律,最后算括号外的乘法;
(8)先算小括号内的,再算中括号内的,最后算括号外的;
(9)先算括号内的,再算括号外的乘法,最后算加法.
解答:解:(1)
×
×
=
;
(2)(
+
)×
,
=
×
+
×
=
+
,
=
;
(3)
×
×39×55=150;
(4)
×(26×
),
=
×26×
,
=6;
(5)
×
+
×
,
=
+
,
=
;
(6)
×[
-(
+
)],
=
×[
-
-
],
=
×
,
=
;
(7)34-34×
,
=34×(1-
),
=34×
,
=
;
(8)[4-(
-
)]×
,
=[4-
]×
,
=
×
,
=
;
(9)
+
×(2.5-
),
=
+
×(
-
),
=
+
×
,
=
+2,
=2
.
| 11 |
| 14 |
| 7 |
| 10 |
| 8 |
| 33 |
| 2 |
| 15 |
(2)(
| 5 |
| 6 |
| 5 |
| 8 |
| 8 |
| 25 |
=
| 5 |
| 6 |
| 8 |
| 25 |
| 5 |
| 8 |
| 8 |
| 25 |
=
| 4 |
| 15 |
| 1 |
| 5 |
=
| 7 |
| 15 |
(3)
| 10 |
| 11 |
| 1 |
| 13 |
(4)
| 40 |
| 13 |
| 3 |
| 40 |
=
| 40 |
| 13 |
| 3 |
| 40 |
=6;
(5)
| 1 |
| 2 |
| 11 |
| 20 |
| 1 |
| 2 |
| 20 |
| 49 |
=
| 11 |
| 40 |
| 10 |
| 49 |
=
| 939 |
| 1960 |
(6)
| 7 |
| 8 |
| 6 |
| 7 |
| 1 |
| 21 |
| 3 |
| 7 |
=
| 7 |
| 8 |
| 6 |
| 7 |
| 3 |
| 7 |
| 1 |
| 21 |
=
| 7 |
| 8 |
| 8 |
| 21 |
=
| 1 |
| 3 |
(7)34-34×
| 26 |
| 27 |
=34×(1-
| 26 |
| 27 |
=34×
| 1 |
| 27 |
=
| 34 |
| 27 |
(8)[4-(
| 3 |
| 4 |
| 3 |
| 8 |
| 1 |
| 2 |
=[4-
| 3 |
| 8 |
| 1 |
| 2 |
=
| 29 |
| 8 |
| 1 |
| 2 |
=
| 29 |
| 16 |
(9)
| 1 |
| 13 |
| 12 |
| 13 |
| 1 |
| 3 |
=
| 1 |
| 13 |
| 12 |
| 13 |
| 5 |
| 2 |
| 1 |
| 3 |
=
| 1 |
| 13 |
| 12 |
| 13 |
| 13 |
| 6 |
=
| 1 |
| 13 |
=2
| 1 |
| 13 |
点评:此题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律或性质进行简便计算.
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