The Wonder of Maths...

How do these people know how to work this out?

1. Key-in the first 3 digit of your mobile phone number (not the 01x number) into the calculator;
2. Multiply by 80;
3. Add 1;
4. Multiply by 250;
5. Plus last four digit of phone number;
6. Plus last four digit of phone number again;
7. Minus 250;
8. Divide by 2.

Now, is it your mobile number???

AMAZING!!!