\documentclass[a4paper,10pt]{classPres}
\usepackage{tkz-fct}

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

\begin{document}
\begin{frame}{Questions flashs}
    \begin{center}
        \huge 30 secondes par calcul
    \end{center}
\end{frame}

\begin{frame}{Calcul 1}
    \huge
    \[
        3 (2 + 9) = 
    \]
\end{frame}

\begin{frame}{Calcul 2}
    \huge 
    Réduire l'expression
    \[
        3x + 5x + 3 - 1 = 
    \]
\end{frame}

\begin{frame}{Calcul 3}
    \huge
    \[
        41 - 78 = 
    \]
\end{frame}

\begin{frame}{Calcul 4}
    \huge
    Calculer l'aire du triangle bleu
    \begin{center}
        \begin{tikzpicture}
            \filldraw[very thick, fill=blue!60] (-2,3) -- (-2,0) -- (3,3) -- cycle;
            \draw (-4,4.5) node {$1cm$};
            \draw[step=1] (-4,-1) grid (5,5);
        \end{tikzpicture}
    \end{center}
\end{frame}

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


\end{document}