(736+821)+264 = (736 + 264) + 821 = 1000+821 = 1821
573+381+919+627 = (573+627)+(381+919)=1200+1300=2500
(736+821)+264 = (736 + 264) + 821 = 1000+821 = 1821
573+381+919+627 = (573+627)+(381+919)=1200+1300=2500