As you might have guessed already, but weren't 100% sure,
5. The last [ - ].UT action is not related to math.

Deadline is very soon, but don't worry! You'll still be able to solve this riddle sometime in the future, but for a reduced prize.
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Oh you didnt guess it which means I'm smarter than y'all. Prize for the last week's riddle has been reduced.

Anyway, I didn't forget about the next week so here's a not rushed at the last second riddle:

??Centurion

First one to guess this one is gonna get Hunter Force and 2 ST