Use figures for most numbers over 10.
Use figures (1, 2, 3, . . .) for almost all numbers over 10. Spell out most numbers under 10.
The exceptions to this rule are words beginning sentences (avoid doing this), and words in the same category.
Example: Fifteen of the girls got 17 or more questions correct, while eleven of the girls got scores of 13 or below.
Percentages are expressed in figures, as are dates, ages, and money.
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"Omit needless words."
Extra words fuzz up your writing and annoy your readers.
Use the simplest wording that will accomplish your purpose.
If you need your piece to be longer, put more content into it, not more words.
Using extra words does not make you look smarter or impress your readers—even your instructors.
To learn more, see: