\newcommand{\valeur}[1] {\Tr{\psshadowbox[fillstyle=solid,fillcolor=LightGreen]{\begin{tabular}{c}\hfq#1\hfq\end{tabular}}}} \newcommand{\reponse} {\Tr{\psshadowbox[fillstyle=solid,fillcolor=LightBlue]{\begin{tabular}{c}\phantom{bonj}\end{tabular}}}} \newcommand{\operation}[1] {\Tr{\pscirclebox[fillstyle=solid,fillcolor=LightOrange]{#1}}} \begin{center} \psset{levelsep=1cm,treesep=5mm,arrows=<-,arrowsize=0.2} \pstree[treemode=U]{\reponse}{ \pstree{\operation{$-$}}{ \pstree{\reponse}{ \pstree{\operation{$\times$}}{ \pstree{\reponse}{ \pstree{\operation{$+$}}{\valeur{6}\valeur{$-4$}}} \valeur{$-6$}}} \pstree{\reponse}{ \pstree{\operation{$-$}}{\valeur{2}\valeur{7}}}}} \kern0.05\linewidth \pstree[treemode=U]{\reponse}{ \pstree{\operation{$+$}}{ \pstree{\reponse}{ \pstree{\operation{$-$}}{ \pstree{\reponse}{ \pstree{\operation{$\times$}}{\valeur{6}\valeur{$-4$}}} \valeur{5}}} \pstree{\reponse}{ \pstree{\operation{$\times$}}{\valeur{2}\valeur{$-3$}}}}} \end{center} %@Commentaire:Une autre façon de faire des calculs avec des priorités.