x,y,z - cifre
xyz in baza 10 = 100x +10y+z
dar xyz=xy+yz+zx
=> 100x+10y+z=xy+yz+zx
=>100x+10y+z=10x+y+10y+z+10z+x
=>100x+10y+z=10(x+y+z)+x+y+z
=>100x+10y+z=(x+y+z)(10+1)
=>100x+10y+z=11x+11y+11z
=>89x=y+10z
y+10z scris in baza 10 este: zy
=>89x=zy
=>x nu poate fi 0, si nici mai mare decat 1 => x=1
=>89=zy
=>z=8;y=9
=>nr este:198
