原式=476+400-2=876-2=874原式=476-400+2=76+2=78望采纳
答:(1)476+398=476+(400-2)=476+400-2=876-2=874(2)476-398=476-(400-2)=476-400+2=76+2=78
476+398=(400+76)+(400-2)=800+74=874476+398=400+76-400+2=78
(476-2)+(398+2)=474+400=874