I need addon for checing inspected element and alert on change

Hey guys
I need an addon which check an inspected element on the page.It’s a number and I want to be notified when that number goes bellow a certain number.
it’s changing constantly and it has commas.
Is there any addon to do that ?
Thanks

SiteDelta Watch | SiteDelta Firefox-Erweiterung

Update Scanner | GitHub - sneakypete81/updatescanner: Firefox addon to monitor web pages for updates. | Update Scanner

… Due to changes in Firefox, Update Scanner has been completely rewritten, and not all of the previous features are finished. …

I’m more familiar with SiteDelta Watch. Began testing Update Scanner a couple of days ago.