I've tried all the tile types on the list but none of work for me
When I add a tile of type "Variable" to a legacy Dashboard, I am able to view and edit the number, with or without decimal points, with no problem. Can you be more specific about what you're doing and what isn't working? Are you using another kind of tile or EZ Dashboard? A screenshot may help.
Variable tiles can be used for Hub Variables, or Hub Variable connectors, on legacy dashboards. They will also display and update any "variable" attribute put in a custom driver.
