דוגמא
<math>A=\left(\begin{array}{cc}
1 & 5\\
-2 & 3\\
<math>R_{3}(AB)=R_{3}(A)\cdot B=\left(\begin{array}{cc}
3 & -7\end{array}\right)\cdot\left(\begin{array}{cc}
-1 & 1\\
1 & 2
\end{array}\right)=\\ 3\left(\begin{array}{cc}
-1 & 1\end{array}\right)+(-7)\left(\begin{array}{cc}
1 & 2\end{array}\right)=\left(\begin{array}{cc}
-3 & 3\end{array}\right)+\left(\begin{array}{cc}
-7 & -14\end{array}\right)=\left(\begin{array}{cc}
-10 & -11\end{array}\right)</math>
==== כפל עמודה עמודה ====