title: working with incredibly large numbers in .NET
body: <p>I'm trying to work through the problems on <a href="http://projecteuler.net" rel="noreferrer">projecteuler.net</a> but I keep running into a couple of problems.</p>
  
  <p>The first is a question of storing large quanities of elements in a <code>List&lt;t&gt;</code>. I keep getting OutOfMemoryException's when storing large quantities in the list.</p>
  
  <p>Now I admit I might not be doing these things in the best way but, is there some way of defining how much memory the app can consume?</p>
  
  <p>It usually crashes when I get abour 100,000,000 elements :S</p>
  
  <p>Secondly, some of the questions require the addition of massive numbers. I use ulong data type where I think the number is going to get super big, but I still manage to wrap past the largest supported int and get into negative numbers.</p>
  
  <p>Do you have any tips for working with incredibly large numbers?</p>