By the definitions on the previous page,
multiplication always involves
dot products of *rows* on the left with *columns* on
the right.

To do any of these calculations:

- Examine the dimensions of the operands.
- The inner dimensions must be equal: 1xN and NxC.
- "Cancel" the inner dimensions to find the dimensions of the result: 1xC.
- Write an empty result matrix with the correct dimensions.

- Now fill in each element of the result.
- Each column on the right is flipped onto a row on the left.
- Each element of the result is a dot product.

Is **Ax** equal to **xA** ?