\documentclass[a4paper,10pt]{classPres}

\usetikzlibrary{snakes}

\author{}
\title{}
\date{}

\begin{document}
\begin{frame}{Calcul mental}
    \begin{center}
        \huge 30 secondes par calcul
    \end{center}
\end{frame}

\begin{frame}{Calcul 1}
    \huge
    \begin{eqnarray*}
        3 \times 35 = 
    \end{eqnarray*}
\end{frame}

\begin{frame}{Calcul 2}
    \huge
    \[ 135 : 3 = \]
\end{frame}

\begin{frame}{Calcul 3}
    \huge
    3 boites coûtent 21 \euro.

    Combien coûtent 12 boite?
    
\end{frame}

\begin{frame}{Calcul 4}
    \huge
    Combien vaut les $\dfrac{2}{3}$ de 12 élèves?    
    \begin{center}
        \begin{tikzpicture}[scale=1.2]
            \foreach \x in {1,...,4} {%
                \draw (\x,0) circle (0.4cm);
                \draw (\x,1) circle (0.4cm);
                \draw (\x,2) circle (0.4cm);
            }
        \end{tikzpicture}
    \end{center}
    
\end{frame}

\begin{frame}{Fin}
    \begin{center}
        \huge On retourne son papier.
    \end{center}
\end{frame}


\end{document}