问题描述: 54.9*0.38和4.05+37.85用简便方法 1个回答 分类:数学 2014-12-07 问题解答: 我来补答 54.9x0.38=(55-0.1)×0.38=55×0.38-0.1×0.38=(50+5)×0.38-0.1×0.38=50x0.38+5x0.38-0.1x0.38=19+1.9-0.038=20.9-0.038=20.8624.05+37.85=41.9 展开全文阅读