| E | R | R | O | R |
| + | O | P | E | N |
| K | N | O | C | K |
See more puzzles containing ERROR, KNOCK or OPEN.
Would you like to see the solution?
The rules for cryptarithm puzzles are simple. Each letter represents one of the digits 0 to 9. Different letters represent different digits. The first digit in a number can't be 0. Your job is to find out what digit each letter represents. Can you solve the puzzle shown here?