APA Style Numbers

In your text, the general APA rule is to use figures to express numbers 10 and above, and use words to express numbers below 10. Of course, there are a few exceptions.

Use figures (not words) to express all numbers when you are discussing a comparison, if they appear in the same paragraph.

For example:

Among the 25 subjects, 4 were eliminated from the study by the second week. (Normally, you would write out the number four, because it is below 10, but in this case, it is part of a sentence where a comparison is being made.)

But

if the two figures appear in the same sentence, and are NOT related to each other, or are not being compared, you should write out any numbers below 10.

Example:

The study continued for 23 years; by the fourth year, only one of the subjects could not be located. (In this case, 23, four, and one are not being compared to each other.)

Also, use numbers to indicate dosage of medication (50 mg), time, dates, ages of subjects in an experiment, scores and points on a scale, and exact sums of money.

Write out the word if the sentence begins with a number; normally, however, if the number is above ten, try to reword the sentence so you don't run into that problem. Also use words to express universally accepted usage of titles, such as the Twelve Apostles, Ten Commandments, The Fourth of July, and so on.

You can combine figures and words to express numbers in the cases of large numbers (6 million) and in the case of back-to-back modifiers (7 sixth- grade girls).

Ordinal numbers (first, second, third, 54th, etc.) are treated the same way as cardinal numbers (one, two, three, 54), and the same rule applies when combining numbers above and below 10, and back-to-back modifiers. That is, write out the words first through ninth; use numerals for 10th and above.