Say you want to calculate your odds of winning the first prize in a lottery. The lottery has 50 numbers to choose from and you buy a ticket which allows you to pick 6 numbers of your choice. To use the "nCr" key, your enter 50 first then press that key, then enter 6 and close the bracket. Finally you press the = key and that should give you the answer. You should get: 15,890,700. Good luck.
