%@Auteur:Véronique Glaçon\par
\renewcommand{\arraystretch}{1.8}
\[\begin{tabular}{|>{\centering}p{1cm}|>{\centering}p{1cm}|>{\centering}p{1cm}|>{\centering}p{1cm}
       |>{\centering}p{1cm}|>{\centering}p{1cm}|>{\centering}p{1cm}|>{\centering}p{1cm}|>{\centering}p{1cm}|}
   \hline $20$ & $\div$ &  & $+$ & $4$ & $=$ & $14$ \tabularnewline
   \hline
    \LCC%
         & \gray & & \gray & & \gray & \\
     $-$ &  & $\times$ & & & & $-$ \tabularnewline
    \ECC
   \hline $8$ & $+$ & $9$ & $\div$ & & $=$ & $11$ \tabularnewline
   \hline
    \LCC%
         & \gray & & \gray & & \gray & \\
      &  & $\div$ & & & & $+$ \tabularnewline
    \ECC
   \hline $7$ & $+$ &  & & $2$ & $=$ & $13$ \tabularnewline
   \hline
    \LCC%
         & \gray & & \gray & & \gray & \\
     $=$ &  & $=$ & & $=$ & & $=$ \tabularnewline
    \ECC
   \hline $19$ & $+$ &  & $-$ & $9$ & $=$ & \tabularnewline
   \hline
\end{tabular}\]   
\renewcommand{\arraystretch}{1}