Is there a term|phrase for a grading assessment that counts the best m of n? I'm assigning weights to different course assessments.

Assessment                    Weight
============================  ======
Assignments (best 5 of 8)       50%
Mid-term exam                   20%
Final exam                      30%


Is there a word or phrase for a grading scheme that counts the best m of n marks? Example: There are weekly assignments worth 10% each, the best 5 of 8 will be counted.
I often see this expressed as "lowest x grades dropped," where x is n minus m.