Does she count up to 12 on one hand but up to five on the other?
This always confused me about the 60 explanation.
It seems to me either you count up to 12 on both hands 24 or 144), or you might as well use the fingers of one hand to point to the joints on the other, thus getting 14 * 5.
And the five itself is suspicious: you can count to 6 * 12 not 5 * 12, since you can raise 0..5 fingers.
Sexagesimal was quite common because it’s so useful (lots of factors). 144 wouldn’t be as handy, I think.
Because of all the factors, in many cases it’s easier to do calculations in base 60 (or 12) in your head, in particular for human scale things where factors like 2/3 make sense. I do this every day without thinking about it. Base 10 is pretty lame.
I think it more likely that ranchers count their animals (moving through a gate?) on fingers (and wind up with base-5 à la Yan Tan Tethera or base-10) while bakers count stationary things in nice rectangles (and wind up with base-6 or base-12), so base-60 was just a reconciliation (have hot dog packs and hot dog bun packs reconciled yet?).
Use a finger on your right hand to point to a joint/pad on your left hand (not including the left thumb). First, your right index finger goes through 12 values, then your right middle finger goes through the next 12 values, and so on. 5*12 = 60.
Maybe because base-60 has some numerological property that makes it easier to use than base-72?
All I can think of off-hand is that 60/5=12 while you can't divide 72 evenly by 5. 72 wins at dividing by 8 & 9, but it might be more rare to split a pile of things into that many.
60's divisors connect more neatly back to base-10, but that's probably a modern era concern, not valid back then.
Also, your thumb has one fewer exposed joint/pad -- the base sort of blends in with the palm, the final joint is much further down -- so they might have felt it's "different".
