/// @@prerequisite affectations 
A = int(10*rand(3,7)); /// \sleftarrow{\normalfont \verb+int+ integer part }
B=A([1,3],$-1:$) /// \sleftarrow {\begin{minipage}[t]{6cm}{\nf{}extracts a submatrix  using row \verb+1+ and \verb+3+\\ and the two last columns of \verb+A+}\end{minipage}}