簡(jiǎn)便運(yùn)算.
578-298      3.64÷4+4.36×25%     23.5+99×23.5.

解:(1)578-298,
=578-300+2,
=278+2,
=280;

(2)3.64÷4+4.36×25%,
=3.64×+4.36×,
=×(3.64+4.36),
=×8,
=2;

(3)23.5+99×23.5,
=(99+1)×23.5,
=100×23.5,
=2350.
分析:(1)可用湊整法將原式變?yōu)椋?78-300+2進(jìn)行計(jì)算;
(2)可將原式化為3.64×+4.36×,再根據(jù)乘法分配律進(jìn)行計(jì)算.
(3)可將原式化為23.5×1+99×23.5,再根據(jù)乘法分配律進(jìn)行簡(jiǎn)便計(jì)算.
點(diǎn)評(píng):當(dāng)算式中同時(shí)含有分?jǐn)?shù)小數(shù)或百分?jǐn)?shù)時(shí),可根據(jù)式中數(shù)據(jù)的特點(diǎn)靈活將它們進(jìn)行互化后再根據(jù)運(yùn)算定律進(jìn)行簡(jiǎn)算.
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科目:小學(xué)數(shù)學(xué) 來(lái)源: 題型:

簡(jiǎn)便運(yùn)算.
(1)578-298
(2)(
1
6
+
1
9
-
1
12
)×4×9
(3)2.5×(1.9+1.9+1.9+1.9)
(4)3.64÷4+4.36×25%

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