I need help with how to calculate the highlighted portion, part f.

Here are the access files in both datasheet view and design view.

9. This problem continues Problem 8. Use the Access Practice.accdb database that you have been working on to complete the following tasks. LO 4-22 a. Go to the Relationships screen and connect the five tables, enforcing referential integrity b. Calculate the total sales for each customer. Include CustomerlD and CompanyName from the Customer table and the calculated sale amount from the Sale Amount Calculation query. Name the query Total Customer Sales C. Generate n e-mail user name for ech employee using the first letter of the employee's first name and the first five letters of the employee's last name, e.g., Rod Smith>rsmith. Include EmployeelD, EmployeeFirstName, and EmployeeLstName in the query. Nme the query Employee-Email-Generator. d. Calculate the total sales for each month. e. Determine which customer had the highest average sales amount. (Hint:Sort in descending order) f. Assume the employees earn a 5 percent commission on sales. Calculate the total commission due to each employee. Use two queries to do these calculations Background for Problems 10 to 14 Ellen Novotny started an online bookstore in 2017. You are Ellen's best friend and promised to help her. Ellen asked you to create a small database to track the information on books and authors. You created the following tables re to search ews Clipboard Sort& Filter Records Find Text Formatting Tables