TeX джерело:

\normalsize{\left(\begin{array}{rrrr}3&4&1&2\\0&3&1&-1\\ 4&3&-2&0 \end{array}\right)+\left(\begin{array}{rrrr}2&-1&3&1\\1&2&-3&0\\ 0&2&3&4 \end{array}\right)=\left(\begin{array}{rrrr}5&3&4&3\\1&5&-2&-1\\ 4&5&1&4 \end{array}\right)}