Math Trick

This math trick is really cool. Just try it!

1. Grab a calculator (You won't be able to do this one in your head)
2. Key in the first three digits of your phone number (NOT the area code-if your number is 01-123-4567, the 1st 3 digits are 123)
3. Multiply by 80
4. Add 1
5. Multiply by 250
6. Add the last 4 digits of your phone number
7. Add the last 4 digits of your phone number again
8. Subtract 250
9. Divide number by 2

Do you recognize the answer?