35/111
\begin{frame}
  \frametitle{The Definite Integral}
  
  \begin{exampleblock}{}
    The integral is a number.
    \medskip
    
    The variable name $x$ does not influence the integral:
    \begin{talign}
      \int_{a}^{b} f(x)dx = \int_{a}^{b} f(t)dt = \int_{a}^{b} f(r)dr
    \end{talign}
  \end{exampleblock}
\end{frame}