Moodle allows you to drop the lowest grade(s) from a category of activities/items in the gradebook.
Requirements:
- The activities/items MUST ALL BE OF EQUAL MAXIMUM VALUE.
- The items must be contained in one category.
Warning:
- At the end of the semester, fill any empty cells with zeros; otherwise, those cells will not be counted as a score when used with the Exclude Empty Grades option.
- Do not have activities with weights of Zero. While this is a common technique to not count an activity, it breaks the rule that all grade items must be of equal value for this option to be available.
Add categories
Step 1
Click Add category, at the bottom of the page

Step 2
Name your category (e.g. Discussions)
Step 3
Click Save changes
Step 4
Enter a Weight or Point Value for the Category
Step 5
Press Enter after entering a value

Step 6
Move activities into your category
- Click the Move icon
- Click the space under the category
- After moving all of your activities, set them to equal parts (if they are all worth the same)
- Press Enter after setting the last value
Set the Category to Drop the Lowest Score
Step 1
Click teh Edit drop-down next to the category

Step 2
Click Edit settings from the drop-down menu

Step 3
Click Show more...

Step 4
Enter the number of lowest scores you wish to drop in the Drop the Lowest textbox

Info
If the Drop the Lowest box is grayed out, it is because one or more grade items in the category are not of equal value. All grade items in the category must be the exact same score for this option to be available. You will need to change all grade items to be the same value before applying this setting.
Step 5
Click the Save changes button
Step 6
In the category, under the Discussion total, you should see the formula
