Mental calculating on everything

quote: Unless you're a math genius and figure out exactly how much energy you will need in advance

I wonder if I become a math genius, I can solve mathematically on everything I see. I could predict how fast the bullet goes, how fast my metabolism is, how long it takes to go to another place, etc.

Preditcting enemy movements, their resources, units, and decision (okay that's actually a psychology-related).

Would that be cool, or it's just a fictional gimmick?

Not very useful.

Competent people already act using fuzzy but accurate information.

Often "don't know" is better than "X 70.36% likely to beat Y in this situation" that'd fail to materialize due to unknowns.