[oftenwrong]

I think the parent is referring to how numbers are constructed verbally.

A number like 52347 would be said like "five ten thousands, two thousands, three hundreds, four tens, seven ones"

Of course, this doesn't really apply above the ten thousands. To say 1,000,000 you have to say "one hundred ten thousands".

[2a0c40]

This is the case for chinese (japanese, despite being from a completely different language family, inherited the system). Digits are grouped by myriads (10^4) instead of thousands (10^3). Accordingly, you would write 10^6 like this: 100,0000