四年级分得的树苗是:=560*(1.-12.5%)*1/7=70棵
五年级分得的树苗是:560*(1.-12.5%)*2/7=140棵
六年级分得的树苗是:560*(1.-12.5%)*4/7=280棵
不懂课追问,看懂望采纳!谢谢!