I happened upon a most wonderful book at the York University library
today, dedicated to determining the formation and identity of the
numbers 20, 30, 40, 50, 60, 70, 80 and 90 in Proto-IE. Of course, I
picked it up, and got so engrossed I was late for class! >.<
I tried checking online for more on this topic, and got only a
Wikipedia entry
(
http://en.wikipedia.org/wiki/Talk:Proto-Indo-European_language ) that
just gave the names of the numbers from 1 to 9 plus the word for
"decad," *-km.t (from *-kemt/*-komt., spin-offs of *dek[e/o]m-t),
resulting in a huge mouthful. This would surely explain the ORIGINS of
the decads, but surely these would be simplified by people who don't
want to spend so much time on an oft-used word.
The one thing missing from the reconstructed series are laryngeals,
but they SEEM rather sensible. I think the author, probably Oswald
John Louis Szemerényi, appears to have done his research. Pity I
couldn't copy even more! But anyway, do you agree with these
reconstructed numbers?
10 = dekm.(t)
20 = wi:km.ti:
30 = tri:kn.t
40 = kWetwr.:kont
50 = penkWe:kont
60 = s[w]ekskont
70 = septm.:kont
80 = okto:kont
90 = newn.:kont
100 = k'mtóm
There's also a little on the ordinal numbers, so I got a page
illustrating that as well.