calculate squares on a grid

From the last couple of days Mr Rees has told us to work out how many squares on the outside of the grid
In maths we had to answer a 10 by 10 grid and show the theory of what we have done and learnt
We have answered 2 ways of how we could figure it out

Here is a way of how we answered

we answered one question like this 10-2 + 10=2 + 10-2 + 10-2, the answer in mathematical would just be n + n-2 + n-2 + n + n-2

This is another n question we did 10+8 + 10+8= 36 in mathematical way it would be n+n+2+n+n+n+2, we had to count up the how many squares are around the outside of the square, And we have tried to figure out the answer.

10 - 1 + 10 - 1 + 10  - 1 + 10 - 1 The answer in mathematical is n-1 + n-1 + n-1 + n-1

does this make sense to you's so far? if it doesn't please tell me what i could fix and you could give me (feedback) on what i should do next thank you!!

  here is the 10 by 10 grid