题目内容
【题目】用你喜欢的方法计算.
12.5×32×0.8 ﹣+ 2.5×[(3.2+1.8)÷0.25] 6.4×0.09+0.01×6.4.
【答案】320;;50;0.64
【解析】
试题分析:①12.5×32×0.8把32拆成8×4,根据乘法的结合律变成(12.5×8)×(4×0.8)计算简便;
②﹣+,先通分在计算;
③2.5×[(3.2+1.8)÷0.25]按四则运算的顺序计算;
④6.4×0.09+0.01×6.4运用乘法的分配律变成6.4×(0.09+0.01)计算简便.
解:①12.5×32×0.8,
=(12.5×8)×(4×0.8),
=100×3.2,
=320;
②﹣+,
=﹣+,
=;
③2.5×[(3.2+1.8)÷0.25],
=2.5×[5÷0.25],
=2.5×20,
=50;
④6.4×0.09+0.01×6.4
=6.4×(0.09+0.01),
=6.4×0.1,
=0.64.
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