The Kelly Formula https://en.m.wikipedia.org/wiki/Kelly_criterion http://www.elitetrader.com/et/index.php?threads/a-new-kelly-formula.291307/
I'd say the power of compounded returns and the difference between arithmetic and geometric averages.
One of the most important attributes of a successful day trader is simply avoiding mistakes and minimizing losses. Put simply: you do not have to do everything …
The 8'th Wonder of the World...Compounding :eek: -- and leverage/options certainly helps too to really cause explosiveness.
I can calculate the motions of the heavenly bodies, but not the madness of people." - Sir Isaac Newton Supposedly, he lost 20 thousand pounds (equivalent of > $2 million pounds today) in the South Sea Company bubble of the 1710s. And he wasn't just a math genius, he was the Master of the Royal Mint at the time (and had been for years), so a financial insider as well.
Too many more answers: https://www.quora.com/What-is-the-most-important-mathematical-idea-in-stock-trading http://www.telegraph.co.uk/finance/10188335/Quants-the-maths-geniuses-running-Wall-Street.html http://time.com/money/3735703/investing-basic-math-equations/ http://bedtimemathproblem.org/mathematics-and-trading/ http://www.wallstreetoasis.com/forums/just-how-much-math-does-a-trader-need