A palindromic number is a number that is the same, backwards and forwards, e.g. 12321. It so happens that for almost all numbers, repeatedly adding a number to its reverse eventually produces a palindromic number. For example:
78 + 87 = 165
165 + 561 = 726
726 + 627 = 1353
1353 + 3531 = 4884
This subject has been interesting as long as we've had computers to calculate all of the repeated addtions. Wolfram MathWorld has a short article about the Palindromic Number Conjecturge. In August of 1985, Creative Computing also published a a short article on palindromic numbers.
I wrote a program to do this repeated addition.. Enter a number into the dialog box and it will start the process of repeated addition until the a palindrome is produced. Note: don't enter the number 196. Do try the number 89, which takes 24 steps.