Bitcoin Value Calculation
There is no mathematical way to determine the value of Bitcoins (or shares of real companies, currencies and similar). It's value is how much people that use it value it. The best indicator what the price is is its exchange rate on various exchanges on the internet like BTC-e, mtGox, Bitstamp and many more. Bitcoins can more or less be related to more traditional currencies when it comes to theoretical background, valuing and more, but take in account Bitcoins are not backed nor managed by anyone or anything. It's all virtual. To look at the price and maybe analyse it you can hop over to bitcoincharts and take a look.