What is the element in row 2, column 3 of $\begin{bmatrix}1 \\ 2 \\ 3\end{bmatrix}\begin{bmatrix}4 & 5 & 6\end{bmatrix}$?

Explanation

1. 01

   A 3 × 1 matrix times a 1 × 3 matrix is a 3 × 3 matrix, and each element is a single product.

2. 02

   Row 2 of the column is 2 and column 3 of the row is 6: $2 \times 6 = 12$.