Q is a Roman numeral?

This isn't directly related to Unicode, but I thought this would be a
good place to ask.

Specifically, I'm curious about figure 14 (Gordon 1982) from WG2 N3218
[http://std.dkuug.dk/jtc1/sc2/wg2/docs/N3218.pdf], which says:
> Whereas our so-called Arabic numerals
> are ten in number (0–9), the Roman nu-
> merals number nine: I = 1 (one), V = 5, X
> = 10, L = 50, C = 100, Đ = 500 (D reg-
> ularly with middle bar, the modern form
> being simply D), a symbol for 1,000 (see
> below), Q = 500,000, and a rather strange
> symbol for 6: ↅ.

Now that Q = 500,000 bit seems a little odd to me. I've never seen
that anywhere else. Does anyone know where it came from? Is there real
usage of Q for 500,000?

—Ben Scarborough
Received on Mon Jan 07 2013 - 19:24:11 CST