Question

A=1*1986+2*1986+3*1986+4*1986
Toate sunt puteri
Calculati ultima cifra a numarului

Answer 1

A=1*1986+2*1986+3*1986+4*1986

U(A)=U(1*1986)+U(2*1986)+U(3*1986)+U(41986)

U(1*1986)=U(1*6)=1

U(2*1986)=U(2*6)=4

U(3*1986)=U(3*6)=9

U(41986)=U(4*6)=6

U(1+4+9+6)=U(20)=0