calculating odds

Hey All,
I've been playing poker for well over a year now, and I think it's finally time to learn what the numbers of poker are.
I post this in the SNG section because that's what I'm specializing in, and so I'm asking you guys.

When someone says that one hand is 4:1 against another hand, I understand that it means that one hand wins 80% of the time, but what I don't understand is how we come up with that answer.

One of the first things that comes to my mind is QQ vs. AK.
I saw on TV that it's almost even preflop.
But what confuses me is that there are only 6 other cards that can make a pair for the AK. I know the AK gets a better chance because there are 5 more cards to come, but ...?

Anyways, I hope this is the correct forum, and I hope the answers to this post help me understand.

Shooby Do