Do you know any method to calculate cube roots ? I suppose you don't, and I don't either. The sense of logic (and this is not a "rule") would be to pick one of the 3 possible answers, not the highest nor the smallest one, you multiply it by itself 3 times, if you get the correct number then that's great, if you get something smaller then there's no need to make any more calculations, you just select the highest answer, and vice-versa.
I call it "logic", not "applying rules" ...