Convert a String (via Left function) into a Number

Hello again,

I have 9 picklists in a Custom Object 1, all with the same values  (1–Unsatisfactory, 2–Needs Improvement, 3–Achieves Expectations, 4–Exceeds Expectations, 5–Outstanding).  My customer has a requirement to calculate the average value for the 9 fields and display the result on the Detail screen.

I tried calculating in a report and exposing it in the detail screen, but that is no longer supported.

I created a custom Number field to capture the Average.  I created a Workflow (When modified record saved) to pull the first character from the Picklist and update the Average field.    No matter what I do I cannot get the value in the picklist to update the Average field. I know that Workflow Rule condition is being met since other Actions are being executed.  Here is the expression in my workflow: