Răspuns :
Răspuns:
●a)11+12+13+14+15+16+17+18+19=(11+19)+(12+18)+(13+17)+(14+16)+15 = 30+30+30+30+15=60+15=90+30+30+15=120+15=135
●b)63+78+25+17+65+32=280 A
●c)270+235+372+518+430+465=(270+430)+(235+465)+(372+518)=700+700+890=1400+890=2290
●d)2439+95+0+1+4105=(2439+1)+(95+4105)+0=2440+4200+0=6640+0=6640
Răspuns:
a) (11+19)+(12+18)+(13+17)+(14+16)+15= 30+30+30+30+15=120+15=135
b) (63+17)+(78+32)+(25+65)=80+110+90= 280
c(270+430)+(235+465)+(372+518)=700+700+890=2290
d)(2439+1)+(4105+95)+0=2440+4200=6640