题目内容
(2009?射洪县)
计算下列各题.能简算的要用简便方法计算. (
|
125×0.25×3.2 |
| ||||||||||||||||
|
5025-2940÷28×37 | (25+25+25)×
|
分析:(2)可将3.2拆分为4×0.8后再据乘法结合律进行简便计算;
(4)可用乘法分配律进行简便计算;
(6)可据整数乘法的意义将25+25+25改成乘法算式25×3进行计算;
其余算式根据四则混合运算顺序进行计算即可.
(4)可用乘法分配律进行简便计算;
(6)可据整数乘法的意义将25+25+25改成乘法算式25×3进行计算;
其余算式根据四则混合运算顺序进行计算即可.
解答:解:(1)(
-
)×(
+
),
=
×
,
=
;
(2)125×0.25×3.2
=125×0.25×4×0.8,
=(125×0.8)×(0.25×4),
=100×1,
=100;
(3)
+(
-
)×
,
=
+
×
,
=
+
,
=
;
(4)
×
+
÷8,
=
×
+
×
,
=(
+
)×
,
=
×
,
=
;
(5)5025-2940÷28×37,
=5025-105×37,
=5025-3885,
=1140;
(6)(25+25+25)×
=25×3×
,
=25.
3 |
4 |
3 |
16 |
2 |
9 |
1 |
3 |
=
9 |
16 |
5 |
9 |
=
5 |
16 |
(2)125×0.25×3.2
=125×0.25×4×0.8,
=(125×0.8)×(0.25×4),
=100×1,
=100;
(3)
2 |
3 |
3 |
5 |
1 |
4 |
4 |
7 |
=
2 |
3 |
7 |
20 |
4 |
7 |
=
2 |
3 |
1 |
5 |
=
13 |
15 |
(4)
3 |
8 |
6 |
7 |
6 |
7 |
=
3 |
8 |
6 |
7 |
6 |
7 |
1 |
8 |
=(
3 |
8 |
1 |
8 |
6 |
7 |
=
1 |
2 |
6 |
7 |
=
3 |
7 |
(5)5025-2940÷28×37,
=5025-105×37,
=5025-3885,
=1140;
(6)(25+25+25)×
1 |
3 |
=25×3×
1 |
3 |
=25.
点评:完成此类题目要注意分析式中数据的特点及内在联系,看是否能够利用简便方法进行计算.
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