D:9=C+R
D=9C+R
R<9
C<R
R-nr natural
R={1,2,3,4,5,6,7,8}
C-nr natural
C={2,3,4,5,6,7}
1)R=1 =>C=0 nu este solutie
2)R=2 =>C=1
D=9*1+2=9+2=11
3)R=3 =>C=2
D=9*2+3=18+3=21
4)R=4 =>C=3
D=9*3+4=27+4=31
5)R=5 =>C=4
D=9*4+5=36+5=41
6)R=6 =>C=5
D=9*5+6=45+6=51
7)R=7 =>C=6
D=9*6+7=54+7=61
8)R=8 =>C=7
D=9*7+8=63+8=71