# 1. CONDITION

How many integers between 100 and 10000 are there such that their representation contains exactly 3 identical digits?
Solution. If the digit that repeats three times is zero, then by adding one of the other 9 digits in front, we get 9 numbers. If the digit $a \neq 0$ repeats in the number, then the number of numbers with different $b, b \neq a$, will be $9 \cdot 4 \cdot 9$. Therefore, in total, there are 333 numbers.

Answer: 333.