VSCode regex find & replace submatch math?

Question

%s@{fileID: \\(213[0-9]*\\)@\\=\'{fileID: \'.(submatch(1)-1900)@

I am using this regex search and replace command in vim to subtract a constant fro

Answer 1

Just to add another example:

I was replacing src attr in img html tags, but i needed to replace only the src and keep any text between the img declaration and src attribute.

I used the find+replace tool (ctrl+h) as in the image: