For example, if a student earns 1 out of 10 extra credit points on an assignment, the gradebook will show an "F" grade.

To fix this, begin by clicking on the "Grades" tab. Next scroll to the extra credit grade item and click the caret next to it, then "Edit"

Scroll all the way down under "Display Options" to the "Managing View" section and check the "Override display options for this item" box. Then uncheck "Grade scheme symbol" and "Grade scheme color."

Finally click "Save and Close"