[ Number Systems ]

On the board, there is a half-erased record

| 2 | 3 |  | 5 |  |
| :--- | :--- | :--- | :--- | :--- |
| 1 |  | 6 | 4 | 2 |
| 4 | 2 | 4 | 2 | 3 |

Determine in which number system the example is written and restore the addends.

#
$23451+15642=42423$ in the 7-based number system.

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