title: How is pi (π) calculated?
body: <p>How can I write a function which will return pi (π) to a given number of decimal places?</p>
  
  <p>Speed is not a concern. I've been looking at <a href="http://bellard.org/pi/" rel="noreferrer">http://bellard.org/pi/</a>, but I still don't understand how to get the nth digit of pi.</p>