I saw this video on Facebook and I'm curious about this. I have very basic questions on this because I can use it but I can't understand the technique.
Link to the video explaining this method on Facebook: https://www.facebook.com/tbar9a/videos/824414374314985/
1) What is this method's name?
2) How does it work? What is the relation between the numbers and the intersections?
3) Is this working for any integer number times any integer number or are there limits?
4) Is there some problem with this problem like negative aspects? I don't know why it isn't standard way for people and students who have problems with math.
5) Why do we have to count the line's intersections from top to down?
6) How does someone invent this method? I have no clue how someone could think about this, not even by chance!
I'm sorry if this sounds very unintelligent or foolish. Also sorry if wrong network, I wasn't sure where to post it.