| Answer | Crossword Clue |
|---|---|
| ISBN | Book ID code number |
| SER | ID number |
| SSN | Payroll ID number |
| CUSIP | ... number (ID on all stocks and registered bonds) |
| AREA | ... code (three-digit number) |
| AREA | ... code (phone number starter) |
| ZIP | ... code (number on a letter) |
| AREA | ... code (part of a phone number) |
| AREA | ... code (part of a telephone number) |
| ONE | Number dialed before an area code |
