40. Excluding numbers starting with 0.
The sum of all palindromic numbers from 1001 to 9999 is 495000.
1001 - 1991, etc = 10, x (2,3,4,5,6,7,8,9) 8 = 80
24
17
40. Excluding numbers starting with 0.
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 10 palindromic numbers between 9000 and 10000 9009,9119,9229,9339,9449,9559,9669,9779,9889,9999!!!
1001 is the smallest 4 digit palindromic number.
The sum of all palindromic numbers from 1001 to 9999 is 495000.
1001 - 1991, etc = 10, x (2,3,4,5,6,7,8,9) 8 = 80
24
17
Assuming leading zeros don't count: 1001
-11
3 digit numbers are lessthan 4 digit numbers
There are 2941 4-digit numbers such no two of its digits differ by 1.