THEM: take four hats and call it a deal  YOU: i would like 1 ball 1 hat and 1 book  THEM: i can maybe do a ball and a hat but i'm not giving up the book.  YOU: then how about 1 ball, and 3 hats  THEM: yea, i can give you one ball and three hats.  YOU: ok 1 ball 3 hats deal.