Math Puzzle

Key in the first three digits of your seven-digit phone number into the calculator. (Note: Do not key in the area code, but the three digits after.)

1. Multiply by 80.
2. Add 1.
3. Multiply by 250.
4. Add the last 4 digits of your phone number.
5. Add the last 4 digits of your phone nmber again.
6. Subtract 250.
7. Divide by 2.