Amazing Math!!

I got this email today and I found it simply amazing!! Try it out :)

**please note the phone number you use must be a 8 digit number

1. key-in the first 4 digit of your handy phone number br 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 at last

Is it your handy phone number???