How many palindromes are between 100 and 10000?

Answer 1

For the group of 3 digit numbers :

Any number from 1-9 can be the 1st digit, any number from 0-9 can be the 2nd digit, the 3rd digit can only be one number that matches the 1st digit.

The number of possibilities is thus, 9 x 10 x 1 = 90.

For the group of 4 digits :

Any number from 1-9 can be the 1st digit, any number from 0-9 can be the second digit, the 3rd digit can only be the one number that matches the 2nd number, and the 4th digit can only be the one number that matches the 1st digit.

Number of possibilities is 9 x 10 x 1 x 1 = 90.

Giving a total of 180 palindromic numbers between 100 and 10000.