THEM: hello, can i have the balls, the book, and 1 hat?  YOU: balls and hats for me  THEM: i am going to need more than just the 1 book. you can have both balls if i can have 3 of the hats.  YOU: balls and three hats for me  THEM: that will not work still. would you like all 4 hats if i can have the balls and book?  YOU: balls and two hats for me  THEM: okay, deal.