And then it leads to separate "uninterpreted" names for each number of fingers that a person can hold up. After that there's a natural route toward place value

And then it leads to separate "uninterpreted" names for each number of fingers that a person can hold up. After that there's a natural route toward place value with units of either one or two hands. Even the shapes of the Roman numerals may have originated from chunking "hands" as units: https://en.wikipedia.org/wiki/Roman_numerals#Hand_signals https://en.wikipedia.org/wiki/Roman_numerals#Hand_signals (although the Romans did use further multiplicative combinations of 5s and 10s, they didn't come up with implicit ways to continue the process indefinitely)