4 introduces the concept of Nash equilibrium and also its relation with the Greece and Europe stand off 42 make a mandatory pair as 2 has a pronoun"this" which has been explained in 4 1 takes the idea forward as is evident by the phrase "can also help us". 5 will come after 1 as it talks about the“game" which has been mentioned in the previous sentences 3 is the last sentence as it raises a question This question will be answered in the subsequent paragraphs