Replacing second digit

Hi all,

Someone on here helped me out before but now im having a few new issues:

Basically in Column A, rows 1-400 (A1:A400) I have a 7 digit number, I want to replace the second digit in that number to an "x" and am finding it hard to write code that works! Any help would be appreciated, I am fairly new to this!

Cheers

=REPLACE(A1,2,1,"X") write on the next column B that formula then drag down the formula

Cant believe it was that easy! I have been messing around for the past hour with much more complex formulas!!! Thanks emina002