Răspuns:
b) 400 + (275 +25) + (60+40) + ( 331 +169) = 400+300+100+500 = (400+100) + 300+500 = (500+500) + 300 = 1300.
c) (71+29) + (62+38) + (48+52) + (99+1) +100 = 100+100+100+100+100 = 500
d) (27+73) + (13+87) +(21+79) + (34+66) = 100 +100+100+100 = 400