I am looking for a way to add/delete visuals based on the selection made in number slicer.
For example: I have a number slicer (from 1 to 10), if the user selects 2 then 2 visuals should be shown; if he selects 5 visuals should be shown.
Also, the the numbers in slicer may vary.
In Power BI, the slicer visual is used for filtering data. It can't change visuals visibility directly based on selected values.
For your requirement, one workaround is to create bookmarks for each selected slicer value and change other visuals visibility based on selection pane. See: https://docs.microsoft.com/en-us/power-bi/desktop-bookmarks