Math prerequisites for understanding LW stuff



I just got a PM with this question: "What would be the minimum intellectual investment necessary to be able to fruitfully take part in the discussion of decision theory on LW?" This is not the first time I've been asked that. Our new discussion section looks like the perfect place to post my answer:

1) Learn enough game theory to correctly find Nash equilibria in 2x2 games all by yourself.

2) Learn enough probability theory to correctly solve Monty Hall, Monty Fall, Monty Crawl all by yourself.

3) Learn enough programming to write a working quine (in any language of your choice) all by yourself.

4) Learn enough logic to correctly solve the closing puzzle from Eliezer's cartoon guide.

Then you're all set. Should take you a few days if you've studied math before, a few weeks if you haven't. No special texts needed beyond Wikipedia and Google.