How many 13-digits number are Palindromic numbers? A Palindromic number reads the same forward and backward, example 1234567654321.  Choose the correct option:
A) 100
B) 610
C) 729
D) 900
E) 9000000
Take the task of building palindromes and break it intostages.   Stage 1: Select the 13th digit   We can choose 1, 2, 3, 4, 5, 6, 7, 8, or 9   So, we can complete stage 1 in9ways   Stage 2: Select the 12th 11th 10th, 9th, 8th, 7th,   We can choose 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9   So, we can complete stage 2 in10ways   IMPORTANT: At this point, the remaining digits are alreadylocked in.   Stage 3: Select the 6th, 5th, 4th, 3rd, 2nd, 1st digit   So, we can complete this stage in1way.   By theFundamental Counting Principle(FCP), we can complete all 5 stages (and thus build a 13-digit palindrome) in(9)(10)(10)(10)(10)(10)(10)(1)(1)(1)(1)(1)(1)ways (= 9000000 ways)   Answer: 9000000
<result>E</result>
How many 13-digits number are Palindromic numbers? A Palindromic number reads the same forward and backward, example 1234567654321.