题目内容
能简便的要用简便计算
|
|
101×
| ||||||||||||||
72×(
|
73×
|
57×
|
分析:(1)先算乘法,再算减法;
(2)可根据乘法交换律及结合律计算;
(3)可将101拆分为100+1后根据乘法分配律计算;
(4)(5)(6)可根据乘法分配律计算.
(2)可根据乘法交换律及结合律计算;
(3)可将101拆分为100+1后根据乘法分配律计算;
(4)(5)(6)可根据乘法分配律计算.
解答:解:(1)
-
×
=
-
,
=
;
(2)
×
×
×8
=
×8×(
×
),
=
×2,
=
;
(3)101×
=(100+1)×
,
=100×
+
,
=76+
,
=76
;
(4)72×(
+
)
=72×
+72×
,
=56+45,
=101;
(5)73×
-
=(73-1)×
,
=72×
,
=14;
(6)57×
+
=(57+1)×
,
=58×
,
=24.
7 |
8 |
5 |
8 |
4 |
5 |
=
7 |
8 |
4 |
8 |
=
3 |
8 |
(2)
7 |
24 |
6 |
13 |
13 |
3 |
=
7 |
24 |
6 |
13 |
13 |
3 |
=
7 |
3 |
=
14 |
3 |
(3)101×
19 |
25 |
=(100+1)×
19 |
25 |
=100×
19 |
25 |
19 |
25 |
=76+
19 |
25 |
=76
19 |
25 |
(4)72×(
7 |
9 |
5 |
8 |
=72×
7 |
9 |
5 |
8 |
=56+45,
=101;
(5)73×
7 |
36 |
7 |
36 |
=(73-1)×
7 |
36 |
=72×
7 |
36 |
=14;
(6)57×
12 |
29 |
12 |
29 |
=(57+1)×
12 |
29 |
=58×
12 |
29 |
=24.
点评:完成本题要注意分析式中数据的特点,然后运用合适的方法计算.
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