Exempt Students

I have look through most of the pages but could not anything on my problem.
When entering grades into the grade book, I need to exempt a student from an assignment. Example John scored 15/15, but Sam has excused absent and missed the in class assignment, what will I enter?

Hello cmfoster1966,

You can either leave that cell empty or you can use a particular icon to mark it as such.
From the main screen's Settings (on the ruler) > Empty cell icons you can define your own.