Let $G=K_1\times K_2\times K_3\times K_4\times ......\times K_n$ and $g\in G$ Then I have to describe Center and $N(g)$ in terms of $K_i$. Where $$N(g)=\{x\in G| gx=xg\}.$$ My attempt: $t\in Z(G)$ therefore $tm=mt$ for all $m \in G$ So $t=(t_1,t_2,......,t_n)$ and $m=(m_1,m_2,......,m_n)$ So individually componentwise we get $(t_im_i)=(m_it_i)$. So $(t_i)\in Z(K_i)$. Is this is sufficent?
Also on same account $s\in N(g)$ then $s_i \in N(g_i)$ Is my arguments are right or need some extra work? Any help will be appreciated.