On Boing Boing today, there was a little entry on Les Stewart, an Australian who spent 16 years and 7 months typing all the numbers from one to one million. Spelled out. Like this:
Augh! Did he do this sober? My gods!
This bit was linked to Rekord-Klub Saxonia, The International World Record Breakers' Club (um, okaaaaay), which has what looks like the final page of Mr. Stewart's typing quest. Okay, I have to admit, I was looking for a typo. I mean, the odds!
And . . . here we go:
nine hundred and ninety-nine thousand, nine hundred and ninety-nine
A spelled-out number does not get any commas. That splits it into two (or more) separate numbers:
nine hundred and ninety-nine thousand [and] nine hundred and ninety-nine
In numerals, that would be:
999,000 [and] 999
Without that comma, it can be read as one number:
nine hundred and ninety-nine thousand nine hundred and ninety-nine
I don't have my trusty CMS handy, but I found this reference on its site:
Q. If numbers must be written out by using words, are commas added in the same places as they would be used for digits? Example: 23,504,070; twenty-three million, five hundred four thousand, seventy. Thanks!
A. No commas should be used when numbers are written out:
103,000 = one hundred three thousand
The longer the number, the more awkward it may seem, but commas would make the number look like a series of smaller numbers, something that doesn’t happen with numerals because there are no spaces, for one thing.
Of course, this is not the only number that's unfortunately split into two. It occurs for the entire length of the page and probably started happening in his first year of typing, say, at number 1,100.
And I'm not even pointing out that and should be left out, for the same reason. (Okay, I just did.)