New user: Basic Math Question

I'm new to the forum and fairly new to poker. I have a bunch of basic questions that I'll be asking over the next few months and I hope you guys can help learn.

I read Caro's site that the odds of being dealt any wired pair is 220-1. I was wondering if somebody could "show me the math" on how you get there.

Thanks,

Drew
PS I'm not doubting the accuracy, just wanna know how to do the work.