I have saved the raster calculation output in the "New File Geodatabase . gdb" . I can see it from "ADD data" menu. but I cannot access to contents of the "New File Geodatabase . gdb" in ArcCatalog to Delete that.
To delete the file, you can either close the program in which it is open and try accessing it again in ArcCatalog, or delete it directly from the operating system by going to its location on your computer and deleting it from there.