To be a 3 digit palindromic number, it must be of the form aba.
I assume that a 3 digit number must be at least 100 (so that 020 for example does not count as a 3 digit number):
Thus there are 9 x 10 = 90 three digit palindromic numbers.
Twenty.
266, 267, 268
a 8-digits palindromic number is a number consisting of a 4-digits number written and then written backward, i.e. 1234 4321 so there are as many palindromic 8-digits numbers as 4-digits numbers so from 1000 to 9999, so there are 8999 palindromic 8 digits number (I assumed that 00011000 is not to be considered as a valid 8 digit number)
There are 9 palindromic numbers between 0 and 100: 11, 22, 33, 44, 55, 66, 77, 88 and 99.
There are 9 palindromic numbers between 400 and 500. A palindromic number reads the same forwards and backwards. The palindromic numbers in this range are 404, 414, 424, 434, 444, 454, 464, 474, and 484.
There are 90 palindromic numbers between 100 and 1000
There are 900 three-digit numbers, ranging from 100 to 999.
infinite
90
9
There are 900000 of them.
There are not just 13 non-palindromic numbers. Most numbers are non-palindromic.
1089
10
1089
The sum of two palindromic numbers is not necessarily a palindromic number. For example, adding the palindromic numbers 121 and 131 gives 252, which is also a palindrome. However, adding 121 and 122 results in 243, which is not a palindrome. Therefore, while some sums of palindromic numbers can be palindromic, it is not a guaranteed outcome.
Twenty.