I'm trying to sum data in Sheet1 from 50+ other sheets in the same file,
using =SUM(EUN1!AD8+EUN2!AD8+SV!AD8....and so on. However, I need to ammend
the formula every time new sheet is added.

Is there a formula which will automatically count the values in the
respective cell in all sheets, irrespectively how many are added?

Thanks a million!