Answer: There are usually 5 judges and 1 or 2 degree of difficulty (DD) judges.
For a SET routine the 5 judges will display their scores, the top score and the bottom score are taken away and the 3 remaining get added together to get your final score.
For a VOLUNTERY routine the 5 judges will display their scores and the DD judges will also display their score. Again the top and the bottom scores are removed, the 3 remaining scores get added together, then the DD score gets added onto that.
The double mini scores are added up the same as the voluntary routine on the tramp