Instructors may add extra credit items to the Moodle gradebook. Note: You cannot make an item extra credit at the time you are creating it. Create the gradebook item or Moodle activity you want to use as extra credit first, then follow the steps below.
From the course course homepage, click Grades.
From the main page of the gradebook, click Setup.
Locate the grade item or activity you want to make extra credit, and click Edit->Edit Settings
In the settings, tick the Extra credit checkbox under the Parent category heading, and click Save Changes.
You now have an extra credit item, as denoted by the + symbol in the Max Grade column. Note that the available points in the Max Grade for this assignment will no longer be counted in the sum total of points available.
You may optionally override the natural weight of grade items, including extra credit, by ticking the box next to the weight and entering a custom percentage.