You can set a grade category to drop the lowest grade. For example, if you have a grade category “Homework” in your grade book, you can elect to drop up to the lowest 20 items in the category.
Note: Drop the lowest only works when all items inside a category are the same point value.
Step 1: From within your course open your grade book by selecting Gradebook setup from the Administration block menu. Make sure the Setup tab is selected.
Step 2: For the category you would like to drop the lowest grades, click the Edit drop down menu located to the right of the category in the Actions column and select Edit settings.
Step 3: Under the Grade category settings, click the Show more… link.
Step 4: Under Drop the lowest, type in the number of lowest grades to drop. When finished, click the Save changes button at the bottom of the page.