"Mrs. Smith, I ain`t got no crayons. Young m..." joke

Mrs. Smith, I ain`t got no crayons.
Young man, you mean, I don`t have any crayons.
You don`t have any crayons. We don`t have any crayons.
They don`t have any crayons.
Do you see what I`m getting at?
I think so. What happened to all the crayons?