By the definitions on the previous page,
multiplication always involves
dot products of *rows* on the left with *columns* on
the right.
So,
To do any of these calculations:

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