\documentclass[a4paper,10pt]{classPres}

\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*}
        87,5 + 3,7 - 3 = 
    \end{eqnarray*}
\end{frame}

\begin{frame}{Calcul 2}
    \huge
    \begin{center}
        Combien font $\dfrac{7}{12}$ de 12 stylos?
    \end{center}
\end{frame}

\begin{frame}{Calcul 3}
    \huge
    \begin{eqnarray*}
        7x + 3x - 5x + 4 = 
    \end{eqnarray*}
    
\end{frame}

\begin{frame}{Calcul 4}
    \huge
    Quelle est la probabilité de tirer une boule verte dans cette urne?
    \begin{center}
        \Ovalbox{
            \begin{tikzpicture}[scale=1.2]
                \draw[fill=red] (0,0) circle (0.4); 
                \draw[fill=red] (1,0) circle (0.4); 
                \draw[fill=red] (2,0) circle (0.4); 
                \draw[fill=green] (0,1) circle (0.4); 
                \draw[fill=green] (1,1) circle (0.4); 
                \draw[fill=green] (2,1) circle (0.4); 
                \draw[fill=green] (0,2) circle (0.4); 
                \draw[fill=green] (1,2) circle (0.4); 
                \draw[fill=blue] (2,2) circle (0.4); 
            \end{tikzpicture}
        }
    \end{center}
\end{frame}

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


\end{document}