Mátrixszorzat:
$$A=\begin{pmatrix}{a}_{11} & {a}_{12}\\ {a}_{21} & {a}_{22}\end{pmatrix}\enspace\enspace
B=\begin{pmatrix}{b}_{11} & {b}_{12}\\ {b}_{21} & {b}_{22}\end{pmatrix}\enspace\enspace
C=\begin{pmatrix}{c}_{11} & {c}_{12}\\ {c}_{21} & {c}_{22}\end{pmatrix}$$
Ha $C=AB$, akkor
$${c}_{11}={a}_{11}{b}_{11}+{a}_{12}{b}_{21} \enspace\enspace {c}_{12}={a}_{11}{b}_{12}+{a}_{12}{b}_{22}$$
$${c}_{21}={a}_{21}{b}_{11}+{a}_{22}{b}_{21} \enspace\enspace {c}_{22}={a}_{21}{b}_{12}+{a}_{22}{b}_{22}$$