HOW TO HIDE/UNHIDE COLUMNS FROM STUDENTS
By doing hiding the column from student view, Instructors are able to enter the grades earned and make the column available with the all of the grades at once. This way all of the students will have access to their grade at the same time. The problem is that students will not receive a notification of the new grade being posted, so they will not know that their item has been graded unless they go into their Grade Center and notice the change. At this moment, it is recommended to post an Announcement in the course or sending an email notifying the students that a grade has been made available.