其它
A robot is facing south-east.  It makes 58 quarter-turns clockwise, then 93 quarter-turns anti-clockwise.  In which direction is the robot now facing? 
Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations
58 quarter-turn clockwise, 93 quarter-turn anti-clockwise, is the same thing as 35 and 1/4 quarter-turn counterclockwise, 35*1/4=8 turns more than 3/4, so it is facing southwest. 