A five-digit palindrome would be of the form ABCBA, where A, B, and C are digits (not necessarily distinct) from 0 to 9 (with A from 1 to 9). We have three possibilities for each of A, B, and C which gives us 3^3 possible 27 palindromes.

-AoPS Staff

You multiply 1 by 0 first and then get 4(1) which is 4

Thank you!