Originally Posted by

**MrJank** Each student at a school is given a 6 digit code (like 123876 or 001233)

(b) How many codes read the same forward as backward

I think I understand this one.. For a 6 digit number to be same in forward/reverse, I would have to count the possibilities of the first 3 digits? I'm not sure why this is or if it is even right.

(d) How many codes contain at least one even digit

If each digit can hold 0-9, and there are only 5 even numbers in that interval... would it be 5^6?

(c) How many numbers contain only odd digits?