I aways figured that they live on a street together, but that they were talent hunted for their incredible math, alphabet, etc skills and asked to move to the street, knowing that they would be on a "Truman Show" type deal. I don't think they have scripts, but they know the cameras are there. Perhaps mechanical cameras, not ones with people carrying them.
So they can talk to the cameras as if they were addressing an audience when there is something specific they want to teach, but otherwise get on with their lives.