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How to Write Numbers Under APA Guidelines

Knowing when to spell out numbers or use numerals for a research paper can be confusing. The general American Psychological Association rule of thumb is to write out any number under 10 and use the actual number if it's over 10, but there are exceptions to this rule and if you're writing for publication or a school assignment, it's helpful to know these exceptions.

Instructions

- 1
  Spell out all numbers under 10 in general; for example, you would write "one," not "1."
- 2
  Use numerical figures to express number greater than 10; for example, you would write "17," not "seventeen."
- 3
  Use the "%" when writing any percentage with a numeral, such as "50%," but not when the number is written out, such as "three percent."
- 4
  Don't use an apostrophe when making numbers plural; for example, "it happened in the 1960s," not "1960's."
- 5
  Spell out common fractions, such as one half, or one third.
- 6
  Use numerals with precise measurements, such as "5.2 inches," "3 cups."
- 7
  Use numerals when numbers under 10 appear in series or in the same sentence as numbers greater than 10; for example, you would write "He hit 5 home runs but took 20 walks." Use numerals when denoting a place in a series, such as "Row 3," "Chapter 5."
- 8
  Write dates, ages and money in figures in general.

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