Ask them to subtract 250
11102674 - 250 = 11102424
Ask them to divide by 2. If they've done everything correctly, they'll be looking at their telephone number.
45113 / 2 = 5551212
Here are the steps again:
Enter the first three digits of their phone number
Multiply by 80
Add 1
Multiply by 250
Add the last four digits of their telephone number.
Add the last four digits of their telephone number again.
Subtract 250
Divide by 2
