计算下列各题,能简便的要简便. ①0.25×4.78×4②65×201③17×23-23×7.
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解:①0.25×4.78×4,
=0.25×4×4.78,
=1×4.78,
=4.78;
②65×201,
=65×(200+1),
=65×200+65×1,
=1300+65,
=1365;
③17×23-23×7,
=(17-7)×23,
=10×23,
=230.
解析分析:(1)运用乘法交换律解答,(2)(3)运用乘法分配律解答.
点评:解答此类题目,要注意分析算式中各数的关系,选择正确的简便算法.