1. Number Collisions
In the sentence “The day the slain woman was to turn 28, 3,000
gathered at a church to recall her life,” the proximity of her age
(assuming it is styled numerically rather than spelled out) and the
number of mourners confuses the eye. Readers may assume, before they
comprehend the sense of the sentence, that the comma after her age and
the following letter space are erroneous and that the digits belong in
one figure.
If the numerical style for the age is correct, revise the sentence to
read, “The day the slain woman was to turn 28, several thousand people
gathered at a church to recall her life.” (This distraction can also
occur when a year, a room or building number, or any other numerical
designation precedes a figure.)
2. Number Ranges
Do not use the word from preceding a number range in which a
dash (or, in this case, as employed often in newspapers and online, a
hyphen) appears: “The Korean War lasted from 1950-1953” should read “The
Korean War lasted from 1950 to 1953” or “The Korean War lasted
1950-1953.” “The class will be held from 7-10 p.m.” is correctly
expressed “The class will be held from 7 p.m. to 10 p.m.” (the first p.m. may be elided) or “The class will be held 7-10 p.m.”
3. Number Names
When you employ specialized terms that include combinations of
numbers or numbers and letters, be sure you’re typing them correctly.
The term in “It’s safe to open your 401K statement again” is correctly
rendered 401(k). The designation for a certain nonprofit corporation sometimes incorrectly styled 501c3 or 501(c)3 should appear as 501(c)(3).
4. Numbers with Hyphenation
I’ve written about hyperhyphenation and hypohyphenation
before (search this site for “hyphens” for more posts on the topic),
but these twin troubles persist, so I will, too: Pay attention when
using hyphens in phrases involving numbers. No hyphens are necessary in
“The electrified fence is 10-feet-high,” because “10 feet high” is a
simple description, not an adjectival phrase describing a noun that
follows immediately (“10-foot-high electrified fence” is correct).
One of those extra hyphens can be donated to the phrase “21-year old
world record,” which refers not to an old world record consisting of 21
years (is that “old world,” as in “old-world charm”?), but to a world
record that is 21 years old.
5. Numbers and Currency
Take care when making references to money: Redundant references such
as “The fine was set at $5 million dollars” or “I found $100 bucks in an
old shoe box” are common. Be consistent in one article or book about
whether you use currency symbols or spell the terms out; the
determination should be based on the level of formality (currency terms
are usually spelled out in more formal writing) weighed against the
frequency of occurrence (numerous and/or technical references to money
are best presented with symbols).
Keep in mind, too, that use of the dollar sign is ubiquitous, but the
cent sign is rare, so if reference is made separately to dollars and
cents, it’s best to spell out both terms: “In 1960, the candy bar cost 5
cents; by the beginning of the twenty-first century, it sold for a
dollar.”
Also, avoid using numerals for orders of magnitude. The figure in
“The binary star is more than 57,000,000,000,000 miles from Earth” is
difficult to read, as is the total in “The budget was 5,666,943,643
dollars.” In the first example, use the term of magnitude: “The binary
star is more than 57 trillion miles from Earth.” Use the same approach
for the monetary figure, which is unnecessarily precise; multidigit
references to currency are often rounded off at two decimals past the
degree of magnitude. “The budget was 5.66 billion dollars.”
From: Daily Writing Tips