[amb5565]

This is really neat to try (it worked on my handheld calculator but did not work on my adding machine with a tape so be prepared for it not to work every time).
First: type in the first 3 numbers of your phone number (not the area code)
Then add 1
Next multiply by 250
Then add the last 4 digits of your telephone number
Next add the last 4 digits of your telephone number
Then subtract 250
The last step: divide by 2.

If this is done correctly, you should see your telephone number as the total.
I did this several times with several different phone numbers and it worked every time on the handheld calculator but was wrong every time on the adding machine. I think I did something wrong on the adding machine.