题目内容
简便计算:
0.25×37.5%+
|
(
|
85×
|
3.14×
|
分析:(1)把小数、百分数化成分数,运用乘法分配律进行简算,
(2)运用乘法分配律进行简算,
(3)把85化成(84+1),然后运用乘法分配律进行简算,
(4)运用乘法分配律进行简算.
(2)运用乘法分配律进行简算,
(3)把85化成(84+1),然后运用乘法分配律进行简算,
(4)运用乘法分配律进行简算.
解答:解:(1)0.25×37.5%+
×
,
=
×
+
×
,
=
×(
+
),
=
×1,
=
;
(2)(
+
)×12×9,
=
×12×9+
×12×9,
=45+48,
=93;
(3)85×
,
=(84+1)×
,
=84×
+1×
,
=79+
,
=79
;
(4)3.14×
+3.14×
-3.14,
=3.14×(
+
-1),
=3.14×0,
=0.
5 |
8 |
1 |
4 |
=
1 |
4 |
3 |
8 |
5 |
8 |
1 |
4 |
=
1 |
4 |
3 |
8 |
5 |
8 |
=
1 |
4 |
=
1 |
4 |
(2)(
5 |
12 |
4 |
9 |
=
5 |
12 |
4 |
9 |
=45+48,
=93;
(3)85×
79 |
84 |
=(84+1)×
79 |
84 |
=84×
79 |
84 |
79 |
84 |
=79+
79 |
84 |
=79
79 |
84 |
(4)3.14×
4 |
5 |
1 |
5 |
=3.14×(
4 |
5 |
1 |
5 |
=3.14×0,
=0.
点评:考查了乘法分配律的运用,灵活运用乘法分配律进行简算.
练习册系列答案
相关题目