a∈1,2....9
bc∈9,18.....81
100a+10b+c=108+100b+10c+a
99a=108+90b+9c |:9
11a=12+10b+c
a=1 imposibil
ptcac≤9,⇒b=a-1
a=2,b=1,c=0 nuverifica prima conditie
a=3;b=2,c=1 nu verifica
a=4;b=3;c=2 nu verifica
a=5 b=4, c=3 nu verifica
a=6 b=5;c=4 verifica;abc=654;bca=546;654-546=108 si 54=6*9
a=7; b=6 c=5 nu verifica
a=8;b=7 c=6 nuverifica
a=9 b=8 c=7 nu verifica
deci singura solotie abc numar=654
