Here at TEC, it’s our job to provide our clients with the best guidance and advice in the editing and flow of their documents. Recently, we had a client ask us about working with numbers in text – how to treat them, when to spell them out, when not to spell them out… There are many questions that can arise when you’re working with numbers!

So, here is a helpful blog to help you out when you need to refer to some basic guidelines on how to treat numbers in text.

Working with Numbers: The Basics

Sometimes it can be confusing to decide how to write your numbers, depending on what kind of document you are working on. It could be a social studies paper, a technical document, a medical journal article… the list could go on and on! None of the styles available to you are wrong, they are just dependent on the situation.

In general, if you are working with medical or technical writing, it is a good idea to use Arabic numerals instead of words in scientific and technical writing for both cardinal and ordinal numbers. But if you’re not familiar with those terms, what does that mean?

Well, Arabic numbers are simply the ten digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, & 9. A cardinal number is a number denoting quantity (e.g., one, two, three, etc.), and an ordinal number is a number defining a thing’s position in a series (e.g., first, second, third, etc.).

For example:

• 6 chemicals
• The sixth chemical
• 9 participants
• The eighth member

In some scientific or scholarly styles, it is recommended that the numbers from one and nine be spelled out, and 10 onwards should be written as digits. This is perhaps the most common style, and one we work with often at The Editing Company.

When to Spell Numbers Out: Exceptions to the Rules

If you are beginning a sentence with a number, always spell the number out:

• Forty-six students were surveyed for the study.

However, if possible, it is often better to reword the sentence. As a bonus, this can also help you remove passive language from your writing.

• The study surveyed 46 students.

If two numbers appear consecutively, spell out whichever one can be expressed in fewer words. It is often a good idea to express units of measure (e.g., centimetres, kilometres, millimetres, etc.) in Arabic numerals. Another option is to reword the sentence. So, you can see how the following example could be confusing:

• We collected 9 1L samples.

To fix the confusion, you could spell out one number:

• We collected nine 1L samples.

Or, to avoid the issue altogether, you could reword:

• We collected nine samples of 1L each.

Lastly, always spell out “one” when it is used as a pronoun, as in “When considering the ethical responsibilities of the study, one must always…”

When to Use Digits

It’s a good idea to use numbers for dates, times of day, page numbers, figures, and notes.

• September 24, 2017
• 1:00 p.m., or 1 p.m.
• Page 25
• Note 7 or Ref. 7
• Figure 2

You should also use digits for percentages, except when they begin a sentence, as the rule above states.

• 67%
• 12.5%
• “Only 25% of students scored above a C+.”
• BUT: “Twenty-two percent of the participants stated they disagreed with the statement.”

What about Fractions?

The Mayfield Handbook of Technical and Scientific Writing recommends spelling out two-word fractions that do not follow another whole number.

• One-half hour
• BUT: 1 ½ hours (because the fraction, 1/2 , follows another whole number, the 1)

Manual-Specific Treatments

Chicago

The Chicago Manual of Style is a little different from the general rules listed above: it recommends spelling out numbers zero to one hundred in non-technical contexts. It also provide helpful guidance for when different types of numbers are mixed, for example, if describing hours and minutes, like seven hours and twenty-nine minutes. Chicago’s rule for these instances is that it allows for mixing numerals and spelled numbers if they describe different categories of objects (like hours and minutes). Just remember, all the numbers in a given category should be treated the same way. 

MLA

The MLA Style Manual dictates that numbers that can be written in one or two words (e.g., two, sixteen, twenty-eight, two thousand, five million) should be spelled out, and numerals should be used for other numbers (e.g., 4 ¾, 672, 2,004, 76,000,000). For ranges of numbers, MLA includes the entire second number for numbers up to 99 (e.g., 1–6, 27–74, 89–99). However, for larger numbers in ranges, only the last two digits are used (e.g., 107–22, 1,111–15), unless more are needed for clarity (e.g., 96–108, 4,367–555).

APA

The APA Publications Manual dictates that words should be used for numbers below nine, and numerals for 10 and above, as we stated in the basics section above. APA has much stricter rules for number ranges than MLA does, and this is due to the style’s emphasis on specificity and clarity in scientific writing, where MLA is often commonly used in liberal arts and studies. APA’s number range rules state that a range of numbers or dates should never be abbreviated.

• pp. 10–45
• 107–124
• 6,001–6,020
• Dates between 1999–2005

Numbers can be tricky to correctly format in many different types of writing, but hopefully our guide can stand as a little cheat sheet for whenever you need a quick checkup! Remember, you can always refer to your style guides for more detailed explanations on how to style numbers in text.