On the account level, you can create grading schemes for your entire institution.
Once a grading scheme is created for your account, instructors can link the grading scheme to their courses. However, once a grading scheme has been used to assess a student, you cannot edit the grading scheme.
Note: Any grading schemes you create on the account level will also display within sub-accounts.
Select the Managed Account in the Courses & Groups drop-down menu.
In Account Navigation, click the Grading link.
Add Grading Scheme
Click the Add Grading Scheme button.
Edit Grading Scheme
Create a title in the Scheme Name field . For each line item, edit the grading scheme name in the name field . Edit the minimum end of each individual range in the To [Number] % field .
If you need to add ranges, place your cursor to the left of a range checkbox and click the Add icon  when it appears. You can remove individual ranges by clicking the Remove icon . When you are finished editing your grading scheme, click the Save button .
Modify Grading Scheme
Your new grading scheme will appear underneath any previously used grading schemes. If you are able to edit the grading scheme, you can edit the scheme by clicking the Edit icon . To delete a grading scheme, click the Delete icon .