I am trying to split an equation inside the align environment, but I get an error message each time I try to add the \begin{split} ... \end{split} lines in the code below:
\begin{align} % requires amsmath; align* for no eq. number
%\begin{split}
A & = B & C & = D \\
& = E & & = F \\
& = G & & = H \\[5mm]
I & = J & K & = L \\
& = M & & = N \\
& = O & & = P
%\end{split}
\end{align}
The code runs perfectly as I typed it above, but as soon as I uncomment the split lines LaTex give me an error: Extra alignment tab has been changed to \cr. I am Any idea of what is not correct in this piece of code? Thanks DK