用简便方法计算4.05×2.9+0.405×70+0.405,急用.

分类: 作业答案 • 2022-03-20 09:37:04

问题描述：

答

4.05×2.9+0.405×70+0.405 =0.405×29+0.405×(70+1) =0.405×29+0.405×71 =0.405×(29+71) =0.405×100 =40.5