题目内容
能简算的要简算
40%×![]() ![]() | 20%×![]() ![]() | ![]() |
75%×125-75%×25 | (![]() ![]() | 15×40%+85×40% |
解:(1)40%×
+60%×
,
=(40%+60%)×
,
=1×
,
=
;
(2)20%×
-20%×
,
=20%×(
-
),
=20%×1,
=0.2;
(3)
×35%+0.25×65%,
=0.25×(35%+65%),
=0.25×1,
=0.25;
(4)75%×125-75%×25,
=75%×(125-25),
=0.75×100,
=75;
(5)(
+
)×45,
=
×45+
×45,
=30+27,
=57;
(6)15×40%+85×40%,
=(15+85)×0.4,
=100×0.4,
=40.
分析:这几个题目都可以运用乘法分配律简算.
点评:乘法分配律是最常用的简算方法,要熟记,并灵活运用.


=(40%+60%)×

=1×

=

(2)20%×


=20%×(


=20%×1,
=0.2;
(3)

=0.25×(35%+65%),
=0.25×1,
=0.25;
(4)75%×125-75%×25,
=75%×(125-25),
=0.75×100,
=75;
(5)(


=


=30+27,
=57;
(6)15×40%+85×40%,
=(15+85)×0.4,
=100×0.4,
=40.
分析:这几个题目都可以运用乘法分配律简算.
点评:乘法分配律是最常用的简算方法,要熟记,并灵活运用.

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