Question

Determinati ultima cifra a numarului
$x={12}^{200} + {23}^{201} + {34}^{302}+ {45}^{403}$

Answer 1

x = 12^200 + 23^201 + 34^302 + 45^403

Uc(12^200) = Uc(2^4) = Uc(16) = 6

Uc(23^201) = Uc(3^1) = 3

Uc(34^302) = Uc(4^2) = Uc(16) = 6

Uc(45^403) = Uc(5^403) = 5


Uc(x) = Uc( 6 + 3 + 6 + 5) = Uc(20) = 0