Sklansky and Expected Value

[Nougat]

I'm not looking to hear from people about what they think about Mr. Sklansky's desire to base many fundamental poker decisions on a mathematical basis as I do agree with him on a conceptual level, though I must admit I am too much the foolish college student to be able to consider all of the factors for determining the overall expected value. My question for the theory forum viewers (as well, I guess, for Mr. Sklansky though I wouldn't presume he would have the time for a relative village idiot)is what factors are taken into account and quantified when determining expected value. I've seen Mr. Sklansky (and others) mention the percentage of possible hands that would make a given, 'x', play (call, raise, fold, check), size of the pot, 'real' chances to win the hand (number of outs), and the odds that an opponent will fold if you bet (percentage chance that bluff will succeed, mentioned in HEFAP). Are there other factors to take into account here? Whenever I see Mr. S' explanation of an expected value play, I end up being very confused. Any help is appreciated.

PS: How do I mathematically determine the number of possible hands? It's something like 52!*51! right?

PS #2: I'm sorry for being dumb. It's all so very new.