- Input the first 3 digits of your phone number (not the area code).
- Multiply by 80.
- Add 1.
- Multiply by 250.
- Add the last 4 digits of your phone number.
- Add the last 4 digits of your phone number again.
- Subtract 250.
- Divide by 2.
- Output result.
Do you recognize the output?
(Source: CuriousMath.com at
"Phone
Number Trick")