There is no multiplication in the above operation.

Actually there is (multiplying the -1 by another -1), but students do not learn it that way

i.e.

7 - (-1)
= 7 - 1 x (-1)
= 7 + (-1) x (-1)
= 7 + 1
= 8

But you do realise that what you've written is the equivalent operation, not the actual.

7 - (-1) = 7 + 1 = 8

This is basically reversing the reverse direction, giving an overall of moving forward on the number line.

If the multiplication approach was to be explained, then the workings should have been shown by the tutor.

Moreover, the (-1) x (-1) = 1 x 1 is also a cancelling of 2 negatives, which is already achieved by -(-1) = + 1 .

So the multiplication approach, while equivalent, is actually more tedious yet not more intuitive.