notam numarul cautat cu a:
a:9=c, rest c+1
a=9c+c+1=10c+1
tinem seama si de faptul ca c+1<9, deci c<8
deci ,
pt c=0, a=1, rest 1
c=1, a=11 , rest 2
c=2, a=21 , rest 3
c=3, a=31 , rest 4
c=4, a=41 , rest 5
c=5, a=51 , rest 6
c=6, a=61 , rest 7
c=7, a=71 , rest 8
Raspuns a∈ {1,11,21,31,41,51,61,71}
