calculate squares on a gird

Mr rees has asked us to work out a 10 by 10 square using n

We answered them in two ways let me show you them both

Here is one way of how we answered,we went 10+10+10-2+10-2 we figured this out by counting all the squares around the outside  so it would be 10+9+9+8 but in a mathematical way it would be n+n-1+n-1+n-2 so the n is equivalent to 10 but this is only the mathematical way to do it you can choose to do it the other way if you want to. 

The second way is to go 9+9+9+9=36 or In the mathematical way It would be n-1+n-1+n-1+n-1 because in this situation the letter n is equivalent to 10 but remember this the n isn't always going to be ten it could be any number. To prove the theory that this way works I will do one more for you


Here is how we prove if it works we do it again we will do 10+8+10+8=36 again in the mathematical way it would be n+n-2+n+n-2 and it still equals 36.

Let me ask you two questions, Answer if you want, does this all make sense to you if not tell me in the comments.The other question is can you think of any other way of figuring out this question If so tell me in the comments, if you have figured out another way of doing this and tell me what I have to work on and if you have liked what I have been doing. 

The grid we have been using.