1. Does there exist a natural number such that after increasing it by 18, the sum of its digits decreases by 18?
Answer: can

Solution. For example, the number 982 works. $982+18=1000$.

|  |  |
| :--- | :--- |
|  |  |
|  |  |
| ${ }_{15-x}$ | $\times$ |

## Grading Criteria.

Only answer: 0 points.

Correct example provided: 7 points.