\frametitle{Math mode - align and equation}
\begin{center}
    For formulas spanning multiple lines you can use:
    \begin{columns}
      \column{0.5\textwidth}
        \texttt{\bs begin\{align\}(...)\bs end \{align\}}
        \begin{align}
          \sum_{n=1}^\infty n =& 1+2+3+4+5+\cdots=\\
                              =& -\frac12
        \end{align}
      \column{0.5\textwidth}
        \texttt{\bs begin\{equation\}(...)\bs end \{equation\}}
        \begin{equation}
          \sum_{n=1}^\infty n = 1+2+3+4+5+\cdots=\\
                              = -\frac12
        \end{equation}
    \end{columns}
  \end{center}