338×39加38用简便的方法怎么做
第1个回答 2016-09-27
338x39+38
=300x39+38x39+38
=300x(40-1)+38x(39+1)
=12000-300+38x40
=12000-300+1520
=12000+1220
=13220本回答被网友采纳
=300x39+38x39+38
=300x(40-1)+38x(39+1)
=12000-300+38x40
=12000-300+1520
=12000+1220
=13220本回答被网友采纳