Many of the activities allow grades to be set.
By default, the results of all grades within the course can be seen in the Grades page, available from the main course page.
If a teacher is not interested in using grades in a course, or just wants to hide grades from students, then they can disable the display of grades in the Course Settings. This does not prevent individual activities from using or setting grades, it just disables the results being displayed to students.
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