Spell out numbers for generally accepted usage, such as idiomatic expressions. One frequently appears in running text without referring to a quantity per se and may appear awkward if expressed as a numeral. When one may be replaced by a or a single without changing the meaning, the word one rather than the numeral is usually appropriate. Other numbers, most often zero, two, and large rounded numbers, also may be written as words in circumstances in which use of the numeral would place an unintended emphasis on a precise quantity or would be confusing.
Any one of the 12 individuals might have been holding the winning ticket. [In this example, one may be superfluous. Depending on the intent, the following may be an equivalent sentence: Any of the 12 individuals might have been holding the winning ticket.]
The study was plagued by one problem after another.
In the article, one researcher estimated that firearms are used for protective purposes in the United States several hundred thousand times annually.
Models were developed to allow for the inclusion of one-time variables.
We appear to be moving from one extreme to another.
On the one hand, the blood glucose concentrations were substantially improved; on the other hand, the patient felt worse.
Medical futility has become one of the dominant topics in medical ethics in recent years.
In one recent case, the bonus amounted to $1 billion.
We ought to bring together in one place all that we have learned on a given subject.
The outcome was a zero-sum gain.
A zero should not be placed to the left of the decimal point of a P value, both because it could be confused with the letter O, and because a P value is always less than 1.0.
Conventional wisdom has it that there are at least two sides to every issue.
Please include an example or two of the following scales.
I would like to ask the patient a question or two about her perception of her illness.
He quoted the Ten Commandments. [See also 10.0, Capitalization.]
Many of the mass-vaccination campaigns have been large, with tens of thousands of persons immunized, and expensive, costing as much as a half-million dollars.
During one of the laboratory runs, it was observed that samples from cases 1, 3, and 9 had faint electrophoretic bands due to suboptimal DNA quality. But: During 1 of the 17 laboratory runs, it was observed…. [See 19.3.2, Combining Numerals and Words, Consecutive Numerical Expressions.]