1) Punch the 1st three digits of your home phone # into your calculator [without the area code].
2) Multiply by 80.
3) Add 1.
4) Multiply by 250.
5) Add the last four digits of your home phone #.
6) Add the last four digits of your home phone # again.
7) Subtract 250.
8) Divide by 2.

Recognize the number? Now, what crazy (genius?) person had the time to think of this?!?