1700-137-363+300
=1700-(137+363)+300
=1700-500+300
=1200+300
=1500简便计算75*103-75*2-7575*103-75*2-75=75*(103-2-1)=75*100=7500简便计算325+99325+99=325+(100-1)=325+100-1=425-1=424