In an assignment group, you can set rules for ignoring/dropping the highest/lowest n number of scores. If an instructor has a group of 10 assignments and wants students to do a minimum of x number of assignments and then will keep the highest y number of assignments, they will have to manually apply zeroes to all of the unsubmitted work in order to then use the "drop the lowest" feature to have the remaining y number of assignments.
Expand the rules available to assignment groups to keep the highest n number of assignments. This will allow an instructor to, say, have 10 assignments from which the students can choose what to do, with the instructor keeping the 3 highest scores. A student could do 3, 5, 10 of the assignments, but it would always just keep the 3 highest. It would likely need some kind of indicator or default action for circumstances where students had not completed a minimum amount to meet the required highest (since calculations would be off if they only did 2 and there were weighted grading).
