| Answer | Crossword Clue |
|---|---|
| TEL | 10-digit no. |
| EXT | No. after a 10 digit number |
| ISBNS | 10-digit book IDs |
| ISBN | 10-digit book ID |
| ISBN | 10- or 13-digit ID |
| ISBN | 10-digit ID at Amazon.com |
| borrows | take (one) from a digit of the minuend in arithmetical subtraction in order to add as 10 to the digit holding the next lower place |
