3.99×0.99×0.39 怎么简算- -

来源:学生作业学帮网 编辑:学帮网 时间:2024/06/04 05:03:51

3.99×0.99×0.39 怎么简算- -

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