问题描述: 3.99×0.99×0.39 怎么简算- - 1个回答 分类:数学 2014-12-03 问题解答: 我来补答 原式=3.99×0.39×1-3.99×0.39×0.01=(4×0.39-0.01×0.39)-(4×0.39×0.01-0.01×0.39×0.01)=4×0.39-0.01×0.39-0.04×0.39+0.000039=1.56-0.05×0.39+0.000039=1.540539简单地说,原式=(4-0.01)×(1-0.01)×(0.4-0.01)然后拆开括号,估计这是最简的了 展开全文阅读