其它
A palindrome is a number that can be read the same forward and backward. For example, the numbers 99, 252 and 4884 are palindromes. How many 3. digit palindrome numbers are there? 
Overseas Competition->Knowledge Point->Calculation Modules->Sequences and Number Tables
From 100-199: 101, 111, 121, 131, 141, 151, 161, 171, 181, 191 (10 numbers)  From 200 - 299: 202, 212, 222, 232, 242, 252, 262, 272, 282, 292 (10 numbers)  From 300 to 399: 10 numbers  From 400 to 499: 10 numbers  $$\cdots $$  From 900 to 999: 10 numbers.  Hence, there are 10 x 9 = 90 three-digit palindromes. 