Storm rules question. Is this allowed at higher level play?

Ive been playing storm for a loong time now but ill let you know this: im horrible at math. So, because i have a hard time keeping track of both my mana pool and storm count i use a pen and paper to keep track. (Also life totals). Would i be allowed to do this at higher level play? Or am i forced to fumble with d 20s? Thanks! Also how was your day :D EDIT : thanks for all the help. Just yesterday i used the last pice of paper in my note pad on storm haha.