D:I=C, +R D=C*I +R
R <I
D:9=C , +R
R <9 =>R={0,1,2,3,4,5,6,7,8}
C=R+1 =>C={1,2,3,4,5,6,7,8,9}
1)R=0 ∧ C=1
D=1*9 +0
D=9
2)R=1 ∧ C=2
D=2*9+1
D=18+1
D=19
3)R=2 ∧ C=3
D=3*9+2
D=27+2
D=29
4)R=3 ∧ C=4
D=4*9+3
D=36+3
D=39
4)R=4 ∧ C=5
D=5*9+4
D=45+4
D=49
5)R=5 ∧ C=6
D=6*9+5
D=54+5
D=59
6)R=6 ∧ C=7
D=7*9+6
D=63+6
D=69
7)R=7 ∧ C=8
D=8*9+7
D=72+7
D=79
8)R=8 ∧ C=9
D=9*9+8
D=81+9
D=89
D={9,19,29,39,49,59,69,79,89}
