11.1. Petya wrote a five-digit number on the board, consisting of different even digits. Vasya erased one digit so that the resulting number is divisible by 18. Which digit did Vasya erase?
Answer: 2.

Solution: The sum of the digits initially equals $0+2+4+6+8=20$. By erasing a digit, Vasya subtracts 0, 2, 4, 6, or 8 from the sum of the digits. The resulting number is divisible by 18, i.e., it is divisible by 9, which means the sum of its digits is divisible by 9. Therefore, Vasya can only erase 2 (otherwise, the sum of the digits will not be divisible by 9).

Criteria: Only the correct answer - 1 point. It is written that the sum of the digits must be divisible by 18 for the number to be divisible by $9(18)-5$ points.