If $A=\left[\begin{array}{cc}1& 3\end{array}\right]$ and $B=\left[\begin{array}{c}2\\ 4\end{array}\right]$, what is the product of $A$ and $B$?

Step 1 ：Step 1: Determine the dimensions of the matrices. $A$ is a 1x2 matrix and $B$ is a 2x1 matrix. Since the number of columns in $A$ is equal to the number of rows in $B$, the matrices can be multiplied.

Step 2 ：Step 2: Multiply the elements of the first row of $A$ by the corresponding elements of the first column of $B$, and then add the products. This will give the element in the first row and first column of the product matrix. $(1\ast 2)+(3\ast 4)=2+12=14$

Step 3 ：Step 3: Continue this process for all rows of $A$ and all columns of $B$. Since $A$ only has one row and $B$ only has one column, the product matrix only has one element.