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.
3
4
-
3
16
)×(
2
9
+
1
3
)                   
125×0.25×3.2
2
3
+(
3
5
-
1
4
4
7
3
8
×
6
7
+
6
7
÷8
5025-2940÷28×37                    (25+25+25)×
1
3
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.
解答:解:(1)(
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
÷8,
=
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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