Numarul are 3 cifre. Daca ar avea patru suma dintre el si rasturnatul sau ar fi mai mare ca 2000.
[tex]\overline{abc}+\overline{cba}=100a+10b+c+100c+10b+a=\\
=101(a+c)+20b=1009\\
u(101(a+c)+20b)=u(a+c)=9\\
a+c=9\Rightarrow a=1,c=8\\
1009=101\cdot9+20b\Rightarrow 1009=909+20b\Rightarrow 20b=100\Rightarrow b=5\\
\overline{abc}=158\\
158+851=1009.[/tex]
