I took a certain 3-digit number, reversed it, got another 3-digit number, and added the two.
The sum was not a palindrome.
I repeated the process, which resulted in another 3-digit number that was still not a palindrome.
Repeating the process twice more I got a 4-digit number, which was a palindrome finally.

What was the 3-digit number we started with the second time?

(In reply to re: computer findings (spoilers) by Daniel)

Given that the reversal of the initial 3-digit number is another 3-digit number, it is implied that the reversed number is different than the original. This assumption eliminates both 181 and 191 being the original numbers, yet it can be argued that that assumption should not necessarily be made as the related subject is  palindromes.   
181 + 181 = 362
                   362 + 263 = 625
                                      625 + 526 = 1151
                                                         1151 + 1511 = 2662
191 + 191 = 382
                   382 + 283 = 665
                                      665 + 566 = 1231
                                                         1231 + 1321 = 2552

As there is an implication that there is but one number as the solution, the assumption will be applied.

192 + 291 = 483, as
291 + 192 = 483
                   483 + 384 = 867
                                      867 + 768 = 1635
                                                         1635 + 5361 = 6996
The 3-digit number of the initial sum is 483.

Posted by Dej Mar on 2018-06-07 04:05:22