1479-399
=1479-(400-1)
=1479-400+1
=1079+1
=1080
980-（80-17)
=980-80+17
=90+17
=107
514+（91-14）
=514+91-14
=514-14+91
=500+91
=591
用简便计算下面各题!不用说,一定要列式出来!不会的别答!没学过的也别答!答啦,你就死定啦!
1479-399
=1479-(400-1)
=1479-400+1
=1079+1
=1080
980-（80-17)
=980-80+17
=90+17
=107
514+（91-14）
=514+91-14
=514-14+91
=500+91
=591