Instead of using numbers to mark an assignment or other assessable work, you can develop your own scale. A basic scale that is enabled by default is Fail / Re-attempt (not yet a pass) / Non-graded pass. You can create custom scales within your topic.
Locate the Administration block
Click on Grades
Click on the Scales tab
Click Add a new scale
Give the scale a Name, for example Grading Scale for Assignment 1
Enter the Scale values. The values range from negative / lowest to positive / highest, and separated by commas. For example: Poor, Average, Good, Excellent