## Precalculus (6th Edition) Blitzer

If $A$ is of order $m\times n$ and $B$ is of order $n\times p$, then the product $AB$ is an $m\times p$ matrix. To find the product $AB$, it is required that the number of columns in matrix $A$ must be equal to the number of rows in matrix $B$.”
Example: If the matrix $A$ is of order $2\times 3$ and $B$ is of order $3\times 5$, then the product matrix $AB$ will be a matrix of order $2\times 5$.