Steps on How to Drop the Lowest Grade 

1. Enter your course.
2. Open the Gradebook tab and select the Overall Grade option.
3. Next, select the Calculation Details button in the top left.
4. Find the category you'd like to drop the lowest grade for (we'll select "Test" for this example) and select Edit Calculation Rules.
   
5. Select the "Enable" toggle under "Category Rule Calculation" then Drop Scores.
6. Enter the desired number of scores to drop (if you select "1" it will drop the lowest score, if you select "2" then it will drop the 2 lowest).
   
7. Select Continue.
8. Then in the bottom right, select Save.