Yeah, I think the wiki statement might be poorly worded, but the way I interpret it is something like: - they learned base 20 counting verbally at home, possib

Yeah, I think the wiki statement might be poorly worded, but the way I interpret it is something like: - they learned base 20 counting verbally at home, possibly simple additions, multiplications, and such too - they learned base 10 english counting as well, and eventually written arithmetic with Arabic numerals - but there was a missing link in having to translate bases that made it harder for them to understand the underlying patterns of written arithmetic or even algebra - having the new written numerals provided that missing bridge, allowing them to round out their understanding To be clear that's just armchair speculation on my part, but that's how I interpreted it. They went from having a challenge of a missing mental connection, to having the advantage of two perspectives. But certainly there's confounders, like perhaps the new numeral system motivated more interest and family support in math.