**Introduction:** An $m \times n$ matrix is a
rectangular array of numbers having $m$ rows and
$n$ columns. The $(i, j)$ entry of $A$, located in the
$i$th row and $j$th column of $A$, is
denoted $A_{j}^{i}$. If $A$is an $m \times p$ matrix and $B$
is $p \times n$, then the product $AB$ has size $m \times n$, and
$$
(AB)_{j}^{i} = \sum_{k=1}^{p} A_{k}^{i} B_{j}^{k}.
$$

**Instructions:** Fill in the entries of the
product, then check your answer. Use the tab key to navigate.

* | = |

Show hints:

Matrix sizes: