\documentclass[a4paper]{article} \usepackage{german,amsmath,amsfonts} \begin{document} $$m = 4,n = 4,s = 4$$$$\left(\begin{array}{ccccc}1&6&8&9&\\ 0&9&3&9&\\ 7&9&3&5&\\ 5&7&0&4&\\ \end{array}\right)\left(\begin{array}{ccccc}2&5&2&0&\\ 8&2&8&6&\\ 6&1&6&6&\\ 1&8&1&3&\\ \end{array}\right) = \left(\begin{array}{ccccc}107&97&107&111&\\ 99&93&99&99&\\ 109&96&109&87&\\ 70&71&70&54&\\ \end{array}\right)$$ \end{document}