Question

Calculati ultima cifra a numerelor : 
2 la puterea 2002
3 la puterea 2003
4 la puterea 2001
5 la puterea 2004

Answer 1

$U(c)2^{2002}=2002:4=500\ \ rest\ \ 2 ;\ \ U(c)2^{2002}=2^2=4\ \ U(c)=4 \\ \\ U(c)3^{2003}=2003:4=500\ \ rest\ \ 3;\ \ U(c)3^{2003}=3^3=27 \ \ U(c)=7 \\ \\ U(c)4^{2001}=2001:2=1000\ \ rest\ \ 1;\ \ U(c)4^{2001}=4^1\ \ U(c)=4 \\ \\ U(c)5^{2005}=>U(c)=5\ \ (cand\ \ baza\ \ este\ \ 5\ \ ultima\ \ cifra\ \ este\ \ 5)$