Question

Determinati ultima cifra a numarului A=$330^{1991} + 331^{1992} + 335^{1993} + 336^{1994}$

Answer 1

   
[tex]\texttt{Notam cu U, functia "Ultima cifra". } \\ \\ U(A)= U[330^{1991} + 331^{1992} + 335^{1993} + 336^{1994}] = \\ \\ U[U(330^{1991}) + U(331^{1992}) + U(335^{1993}) + U(336^{1994})] = \\ \\ U[0 + 1 + 5 + 6] = U[12] = \boxed{2}[/tex]