Thanks to a bit of slight of hand shared by Comment, this can be done.
You need several fields to do this.
Define sCount as a "Count of" the CourseNum field (any nonempty field will do).
Define cReciprocal as 1/GetSummary ( sCount ; CourseNum )
Define sCourseCount as a "total of cReciprocal" summary field.
Put sCourseCount in a header, footer or grand summary part to show the count you've specified.
It works great! Thanks for the help.
This is brilliant Phil and comment. But how does it work??