but hey, don't we have ten fingers?
most people have ten fingers, with five fingers on each hand. the most common way to display a number manually is to just have that amount of fingers extended. sure, there's more complicated things you can do, (hi there, computer science nerds who use their fingers to count in binary!) but if you're not particularly dextrous, like me, then you probbo have trouble moving all of the fingers on one hand separately from one another. the simplest method limits you to displaying five fingers on one hand, which means after five, you need to use another hand. we can notate the usual decimallike finger counting method like this:
now hold on. isn't that a bit wasteful? I mean, for every one of these, one hand has either zero or five fingers extended. so what if we take advantage of how you have two hands? let's say that after you count to 5, instead of just using your other hand as though it were just more fingers on your first hand, you start over at zero, and use your other hand to count sixes:
congratulations, you are now counting in seximal! using both hands, this gets you all the way up to fifsy five. all that's left is to decide which hand represents ones and which hand represents sixes. I recommend using the left hand for ones and the right hand for sixes, so that if you're using this to show a number to someone, they can "read" your hands the same left to right order they'd read an ordinary seximal number in.
for the record, I'm not the first person to suggest this finger counting method; it's used by referees in the NCAA, and far before that it was (and still is!) used by yam farmers in Papua New Guinea.