Răspuns :
1000a+100b+10c+d+100a+10b+c+10b+c+c+3d=2020
1100a+120b+13c+4d=2020
asa este rezolvarea apoi trebuie sa dai factor comun,dar poti sa atasezi cerinta?
1000a+100b+10c+d+100a+10b+c+10b+c+3d=
1100a+120b+12c+4d=2020
550a+60b+6c+2d=1010
275a+30b+3c+d=505
La 275a<505=> a=1
=> 30b+3c+d=230
B=7
C=9 C=8 C=7
D=1 D=6 D=9
1100a+120b+12c+4d=2020
550a+60b+6c+2d=1010
275a+30b+3c+d=505
La 275a<505=> a=1
=> 30b+3c+d=230
B=7
C=9 C=8 C=7
D=1 D=6 D=9