To add two matrices together, we add the corresponding elements together. That's all there is to it.
So here's a straightforward example:
We add the element in row 1, column 1 in the first matrix, to the element in row 1, column 1 in the second matrix and put the result in the position row 1, column 1 in the resultant matrix. Then do the same for the other five elements.
Notice that we can only add two matrices that are the same shape, since we need every element in the first matrix to have a corresponding element in the second.
So we can't add a 2x3 matrix to a 3x2 matrix.
We use the same idea for subtracting matrices. Here's those two matrices from above, but this time instead of adding we'll subtract the second from the first.
Now here's a few for you to practise on. In each case, first add the pairs of matrices, then subtract the second from the first.
