How to Make a Fair Offer to a 200 Dollar Offer?

You started by identifying the size of the pie to be split. Then you showed him why his offer wasn't fair by proposing a hypothetical offer. He comes back and does what people expect, yotoing the case witches. But at the end of the day, i didn't make any counter argument. The 25 hundred was a totally arbitrary number. So until he gets below 13 hundred, i don't count anything.