9126-998简便计算怎么算？解：998＝1000-29126-998＝9126-1000+2……多减了2，要再加上2＝8126+2＝8128
1758-998=1758-(1000-2)=1758-1000+2=758+2=760
=1758-1000+2=758+2=760
1758-998=1758-（1000-2）=1758-1000+2=760
