2. A palindrome is a natural number that reads the same from left to right as from right to left. Find all four-digit palindromes that are equal to the sum of two three-digit palindromes
Answer: 1111 and 1221.

Instructions. Since $1111=505+606$ and $1221=555+666$, the numbers specified in the answer are suitable. The sum of two three-digit numbers is a three-digit or four-digit number starting with 1. Since it is a palindrome, it ends with 1. The hundreds and tens digits must be the same in the four-digit number, and thus, the sum of the tens digits from the three-digit palindromes is 0 or 11. The sum of two digits cannot be 22 or more. There are no other solutions.

Criteria. Only one number: 1 point.

Two numbers without justification that there are no others: 3 points.