Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2012 Question 32

Math Olympiad Vault · MathNet 2012

Question 32

A positive integer whose 1's digit is not 0 is called a *palindromic number* if the number remains the same when its digits are read in reverse order. For example, the number $12321$ is a palindromic number, since the number obtained by reading its digits in reverse order is the same $12321$, while $1234$ is not since the number $4321$ is obtained if its digits are read in reverse order. How many palindromic numbers are there which are less than or equal to $2012$?