Notepad++ Replace regex match for same text plus appending character

I have a file with text and numbers with a length of 5 (i.e. 12000, 11153, etc.). I want to append all of these numbers with a 0. So 11153 becomes 111530. Is this possible in Notepad++?

I know I can find all numbers with the following regex: [0-9]{5}, but how can I replace these with the same number, plus an appending 0?

In the replacement box I tried the following things:

• [0-9]{5}0 - Which it took literally, so 11153 was replaced with [0-9]{5}0
• \10 - I read somewhere that \1 would take the match, but it doesn't seem to work. This will replace 11153 with 0
• EDIT: \00 - Based on this SO answer I see I need to use \0 instead of \1. It still doesn't work though. This will replace 11153 with

So, I've got the feeling I'm close with the \1 or \0, but not close enough.