Any explanations for it?

Worked for me

try this out see if it works for you

Ignore your area code & using only 7 digit phone:
1) key-in the first 3 digits of your phone number into the calculator
2)multiply by 80
3) then plus 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 the answer your phone number???

I just realized that it may work with any 7 digit number combination. It doesn't even have to be a phone number. The numbers used in steps 1,5,6 and mixed with other steps always bring you back to those original seven numbers.

Maybe.

ok, for example 123-456-7890

Ignore your area code & using only 7 digit phone:

1) key-in the first 3 digits of your phone number into the calculator

x=456
ans=x

2)multiply by 80

ans=x*80

3) then plus 1

ans=x*80 +1

4) multiply by 250

ans=(x*80+1)*250=2000x + 250

5) plus last four digit of phone number

y=7890
ans=2000x + 250 +y

6) plus last four digit of phone number again

ans=2000x+250+2y

7) minus 250

ans=2000x+2y

8) divide by 2 at last

ans=1000x+y
ans=1000(456)+7890
ans=4567890


It's just a math trick. Doesn't matter what number is used. You could do something similar for any length number.

Hmm i thought so.