These three sentences exemplify incorrect insertion or omission of hyphens in numerical references. Each sentence is accompanied by a discussion and a revision.
1. The two albums have sold close to 30-million copies combined worldwide.
The combination of a numeral and a word expressing an order of magnitude is never hyphenated; the usage, a simplified version of the cluttered-looking numerical representation 3,000,000, is not a phrasal adjective: “The two albums have sold close to 30 million copies combined worldwide.” (This is true even when the number is a phrasal adjective: “The 30 million figure is unprecedented,” though it is better to relax such a statement to read, “The figure of 30 million is unprecedented.”) “The 30-million-dollar figure is unprecedented.”
In such usage, the number is often spelled out: “The two albums have sold close to thirty million copies combined worldwide.” No hyphen is required in this case, either (“The thirty million figure is unprecedented”), though, again, it reads better in a more relaxed state (“The figure of thirty million is unprecedented”).
When yet another word is included to form a phrasal adjective, however, whether the number is in numeral form or spelled out, hyphenate all three elements: “The 30-million-dollar figure is unprecedented”; “The thirty-million-dollar figure is unprecedented.”
2. These phases are often subdivided into 30, 60, and 90-day segments to manage specific milestones with greater precision.
This sentence refers to segments of 30, 60, and 90 days’ duration, but the word day in the phrasal adjectives “30-day” and “60-day” has been elided because the use of the word in “90-day” makes it clear that the unit of time is implied for all three numbers. However, when this technique, called suspensive hyphenation, is employed, the hyphen must be retained after all three figures: “These phases are often subdivided into 30-, 60-, and 90-day segments to manage specific milestones with greater precision.”
3. We anticipate that significant unplanned outages of the network will occur approximately five-ten times a year.
If the numbers in this sentence were treated as numerals, the correct style would be “5–10 times a year,” but an en dash should not be used in a number range when the numbers are spelled out (nor should a hyphen, which, as here, is often used erroneously in place of the dash): “We anticipate that significant unplanned outages of the network will occur approximately five to ten times a year.” (Some publications deliberately use hyphens in number ranges because a hyphen takes only a single keystroke to type.)
Today’s video: Both vs. Neither
Very good article, Mr. Nichol. I especially like this:
“The combination of a numeral and a word expressing an order of magnitude is never hyphenated; the usage, a simplified version of the cluttered-looking numerical representation 3,000,000, is not a phrasal adjective.
Also, expressions like 5-10 and 5 – 10 look too much like “5 minus 10”, which in this case equals – 5. Also, I still side with those who believe that, with few exceptions, single-digit numbers (and perhaps ten, also) should be written out in words in text. Hence “five to ten” or “five through ten”, depending on the context.
Some references state that all numbers from zero through ninety-nine should be spelled out when they are included in text. I don’t agree, but I have seen this “rule” in writing.
The exceptions in using the single digits in text include such things as technical and military expressions such as
(1, 1) dimethylhydrazene and (1, 3) dibromobenzine, from chemistry,
and when using ordinal numbers, the 6th Fleet, the 5th Air Force, the 3rd Army, the 2nd Marine Division, and the 1st Corps.
In the U.S. Army, it is traditional to use Roman numerals for numbering corps, for some reason; e.g. I Corps (the first Corps), V Corps, VII Corps, and X Corps. In Army jargon, “I Corps” is spoken aloud as “Eye Corps”.
This is a bit odd because Arabic numbers are used for numbering brigades, regiments, divisions (in the Army or the Marine Corps), field armies, and army groups. Army groups have been rarely seen except in the case of extreme wars, and in Western Europe in WW II there were the 6th Army Group, the 12th Army Group, and the 23rd Army Group (mostly British and Canadian) on the Allied side, where the numbers were chosen arbitrarily.
During the Korean War, the two prominent American corps were the I Corps and the X Corps, and the latter contained the 1st Marine Division as well as two Army divisions. These corps, as well as South Korean ones, and units from other nations of the U.N., made up the 8th Army.
The British Commonwealth had a different 8th Army that fought in North Africa and Italy during World War II.