Latex on wikia

\(y=x+2\)

$${3 ~ \times ~ 2 ~ = ~ 6}$$

\( \newcommand{\matr}[3]{{#1}_{#2, #3}} \matr{X}{1}{2} \)

aaa

\( \require{AMScd} \begin{CD} K(X) @>{ch}>> H(X;\mathbb Q);\\ @VVV           @VVV \\ K(Y) @>{ch}>>  H(Y;\mathbb Q); \end{CD} \)