Knowledge required to build your own integer class?

Question

Upon reaching a brick wall with the .Net framework's lack of a BigInteger class (yet), I've decided I'd like to develop my own as an exercise (I realize open source alternatives exist). What hoops do I need to jump through to be able to develop this? Is there any particuliar knowledge pieces that I probably wouldn't have?

edit: side question. Which data type would you use to represent the numbers inside of your new big integer class?

Answer 1

Arbitrary precision arithmetic?

Edit: To represent your numbers you will probably want a resizeable array of integers.