[tex]1990^{1996} = (199 \times 10)^{1996} = 199^{1996} \times 10^{1996} \\
\texttt{Ultimele 1996 cifre ale numarului sunt zerouri, dar } \\
\texttt{ne intereseaza ultimele 1997 cifre.} \\
\texttt{Va trebui sa aflam ultima cifra a numarului }199^{1996}. \\ \\
U[199^{1996}] = U[199^{2 \times 998}] = U[(199^2)^{998}] = 1^{998} = \boxed{1} \\ \\
\Longrightarrow~~ \texttt{Ultimele 1997 cifre sunt: } \\ \\
\boxed{\underbrace{100000000....00000000}_{\texttt{1 urmat de 1996 de zerouri}}}[/tex]
