Dunno if meron nang ganitong topic. Kung wala pa try this out.
1. Key in the first 3 digit of your phone number into the calculator.
2. Multiply by 80.
3. Add 1.
4. Multiply by 250.
5. Plus last 4 digit of your phone number.
6. Plus last 4 digit of your phone number again.
7. Minus 250.
8. Divide by 2 at last.
Is this your phone number???