$13.$ With the Professors table still open in Datasheet View. Add a Calculated Currency field called Monthly that divides the Salary field by $12.$ Save the changes to the table and close it$.$

$14.$ Open the TeachingAssistants table in Datasheet View. Sort the records in descending order by Stipend. Save the changes to the table and close it$.$

$15.$ Open the Professors table in Datasheet View and hide the ProfEmail and HireDate fields that currently have no data. Save the changes to the table and close it$.$