21.3×1.7-0.7=21.3×(1.7-0.7)=21.3×1=21.3所以答案是21.3。谢谢😜
=21.3×(1+0.7)-0.7=21.3+14.91-0.7=35.51
这已经是简便方法了,那里还有什么简便方法?
21.3*(1+0.7)-0.7=21.3+21.3*0.7-0.7=21.3+(21.3-1)*0.7=21.3+(20+0.3)*0.7=21.3+14+0.3*0.7=21.3+14+0.21=35.51