问题描述: 199.4*19.93-199.3*19.92的简便计算 1个回答 分类:数学 2014-11-04 问题解答: 我来补答 199.4×19.93-199.3×19.92=(199.3+0.1)×19.93-199.3×(19.93-0.01)=199.3×19.93+19.93×0.1-199.3×19.93+199.3×0.01=1.993+1.993=(2-0.007)+(2-0.007)=4-0.014=3.986 展开全文阅读