Number

1. In general, please use words to express numbers zero through nine, and please use numerals to express numbers 10 or above; However, there are exceptions to this general guideline for number usage. There are cases in which you should always use words to express numbers, even numbers 10 and above, and likewise, there are cases in which you should always use numerals to express numbers, even numbers zero through nine.
Example: The study had three conditions.
Exception: Fifty percent of the students received the intervention.
2. In general, please use numerals to express numbers 10 and above, and please use words to express numbers zero through nine; However, there are exceptions to this general guideline for number usage. There are cases in which you should always use numerals to express numbers, even numbers zero through nine, and likewise, there are cases in which you should always use words to express numbers, even numbers 10 and above.
An example: There were 15 psychologists at the clinic.
An exception: The number must be multiplied by 2.
3. More detailed information about Numbering according to APA 7th guidelines (in Indonesian: BAHASA) can be found in the following link:
Numbering APA 7th edition