Publications generally use one of two systems of referring to numbers: Spell out numbers to ten and use numerals for all larger numbers (with some exceptions such as informal usage of large round numbers such as “a thousand” or “a million”), or spell out to one hundred and use numerals otherwise (with the same exceptions). Beyond that, several subtle rules and conventions exist, often pertaining to use of punctuation and other symbols such as hyphens. This post presents five sentences that include types of errors pertaining to such use; each example is accompanied by a discussion and a revision.
1. The twelve jurors deliberated for 21/2 days before reaching their unanimous verdict.
In a mixed fraction, the fractional element must be separated from the whole number with a letter space (unless the second element is formatted as a case fraction, with small numerals set vertically above and below a horizontal line): “The twelve jurors deliberated for 2 1/2 days before reaching their unanimous verdict.”
2. To that end, we suggested in 2014 12 ways our product contributes value.
Two separate numerals placed consecutively, even when separated by punctuation, can confuse the reader’s eye, so recast the sentence so that the numerals are not adjacent: “To that end, in 2014, we suggested 12 ways our product contributes value.” (As mentioned above, many publications style numerals one hundred and below as words, which would obviate the problem shown here, but the publication this sentence is excerpted from uses Associated Press style, which spells out numerals only up to ten.)
3. An overwhelming majority of 18-to-29-year-olds get news from social media like Facebook.
Number ranges involving more than just a pair of numbers are often treated using suspensive hyphenation, with the second element of a phrasal adjective, which would normally be repeated in two similar phrases, elided because it the omitted element is obvious from the context. Here, no symbol serves to bridge the number range; that function is performed by to, and the hyphens link elements of a phrasal adjective: “An overwhelming majority of 18- to 29-year-olds get news from social media like Facebook. (In a sentence referring, for example, to people ages 18–29, the symbol used is often an en dash, not a hyphen, though many newspapers and some other publications use the latter symbol.)
4. More than four-out-of-five members of that demographic use social media sources to read and watch news reports.
The expression “four out of five” does not require hyphens; the phrase accompanies but does not modify members, so is not a phrasal adjective: “More than four out of five members of that demographic use social media sources to read and watch news reports.” (The same is true if numerals are used in place of words.)
5. 80-percent believe the region is a great place for career growth, 88-percent say it’s a prime place for innovation, and 70-percent say the Bay Area’s economy is better than the national one.
By convention, a number that begins a sentence is spelled out regardless of the prevailing style about spelling out numbers or using numerals, and numbers representing percentages are not hyphenated to the word percent: “Eighty percent believe the region is a great place for career growth, 88 percent say it’s a prime place for innovation, and 70 percent say the Bay Area’s economy is better than the national one.”