should you write out numbers in a research paper

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When to spell out numbers in scientific writing

• by kayciebutler
• August 3, 2021 August 3, 2021

When to spell out numbers in scientific writing can be tricky, and how/when to do this is one of the most common questions I get. And I get it…sometimes they are numerals and sometimes they are spelled out, and this can seem both arbitrary and not worth your time to figure out.

If you are anything like I was when writing, sometimes you just have more important things to worry about than stressing over what seems like trivial details – like if your numbers should be spelled out or written as numerals.

Numbers are one of those parts of scientific writing that, when done correctly, blend seamlessly into the overall document and lead to this assumption that they are just a trivial detail.

Unfortunately, incorrectly written numbers can make your paper difficult to understand and can even lead a reader astray when interpreting your science.

Luckily, the rules for writing numbers are actually quite specific and not so tough once you know what to watch out for.

And here they are, all in one place for your writing needs! Enjoy!

Skip to your scenario

Or straight to the INFOGRAPHIC!

• Except: Figures and tables
• Except: Dates and times
• Except: Statistics and counting
• Mixed numbers – numbers below and above 10 in the same sentence
• Except: At the beginning of a sentence
• Writing a number with a unit
• Two numbers in a row

To learn how to spell out numbers in a video

Most common situations for when to spell out numbers, –>zero-nine – generally spell out.

In general, the numbers zero-nine are spelled out when written in a sentence.

“The experiment was repeated five times.”

NOT: “The experiment was repeated 5 times.”

*Exception – Figures/Tables

Figure, table, and equation numbers should always be Arabic numerals.

Figure 1 , Table 2 , Equation 3

Not: Figure One , Table Two , Equation Three

Dates and times should always be Arabic numerals.

July 4, 1995, 4 July 1995, 10 p.m.

*Exception – statistics/counting

For statistics or counting purposes, the digits 0-9 can be written numerically.

“W e detected the protein in 9 of the 10 tested samples.”

“There were 5 participants in the study.”

->10, 11, 12 and higher – generally numerical

In general, numbers 10 and higher are written numerically.

“There were 15 participants in the study.”

NOT: “There were fifteen participants in the study.”

->Retaining consistency within a sentence

When multiple numbers are in the same sentence, it is easier to read if they are either all spelled out or all written numerically.

“The final results showed that 2 patients had no visible benefit from the treatment, 8 patients experienced some tumor shrinkage, and 12 patients experienced complete tumor regression.”

“The final results showed that two patients had no visible benefit from the treatment, eight patients experienced some tumor shrinkage, and twelve patients experienced complete tumor regression.”

Not: “The final results showed that two patients had no visible benefit from the treatment, eight patients experienced some tumor shrinkage, and 12 patients experienced complete tumor regression.”

->Beginning a sentence with a number – always spell out

Any number that starts a sentence should be spelled out, no matter the number.

“ Twenty participants returned for the follow-up study.”

Not: “ 20   participants returned for the follow-up study.”

“ Two thousand, two hundred and ninety six participants returned for the follow-up study.”

NOT: “ 2,296 participants returned for the follow-up study.”

However, writing out numbers at the start of a sentence can get a bit ugly, as seen from the last example above. There are several ways to handle this:

• Add the number in parentheses

“ Two thousand, two hundred and ninety six (2,296) participants returned for the follow-up study.”

• Rearrange the sentence to avoid

“For the follow-up study, 2,296 participants returned, and their progress was measured.”

*Exception – chemical names

The one exception is for chemical compounds with a number in their name. Always write this numerically, even when it starts a sentence.

“ 4 -methacryloxy-2-hydroxybenzophenone was the best-performing monomer.”

HOWEVER, I generally suggest ALL sentences starting with a number we reworded to avoid this entirely:

“We found that 4 -methacryloxy-2-hydroxybenzophenone was the best-performing monomer.”

->Writing amounts with a unit

The general rules on spelling out numbers zero-nine do not apply when writing a number attached to abbreviated units, generally in materials/methods sections.

The number should match the unit – if the unit is written out, the number should be written out. If the unit is abbreviated, the number should be abbreviated.

For example, all of the following are correct:

5 hrs, 5 mL, 5 °C, 5 %

five hours, five milliliters, five degrees Celsius, five percent

And you would not want to write

five hrs, five mL, five °C, five %

Uncommon Situations for when to spell out numbers

->two numbers in a row.

When two numbers appear back-to-back, there are two options:

• Spell out the number that is easiest to spell

NOT: “There were 12 100 -mL samples.”

“There were twelve 100 -mL samples.”

• Rearrange the sentence to avoid the problem

“ There were 12 samples of 100 mL each.”

->Fractions

In writing text, fractions should be spelled out, unless an exact quantity has to be conveyed:

• In written text

“ Two-thirds of the patients…”

• To convey an exact quantity

“The results showed that 17/58 samples tested positive.”

Infographic – When to spell out numbers in scientific writing

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Guidelines and Rules for Presenting Numbers in Research Papers

Updated: May 7, 2020

Since numbers are at the heart of research, you should know common rules regarding presenting numbers representing quantitative data in research papers. Knowing these rules will be helpful for writing the material and method section as well as other sections of the paper. If you are aiming to publish in a scientific or scholarly journal, you should check the Guidelines for Authors page of the journal you are targeting for the specific style guide that they follow. Since there are some variations found in different style guides, this will be important to know which guide they adopt. If they do not give this sort of information, it can be helpful to follow some common guidelines prescribed from respected sources like the Council of Scientific Editors. For more detailed coverage of presenting numbers, statistics and mathematical equations in research papers check out: Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers, The Chicago Manual of Style, and How to Report Statistics in Medicine. My apologies for instances where certain math characters were lost in copying below, specifically those related to exponents and superscript in scientific notation.

1. In scientific and technical texts, with a focus on quantitative data, represent a number with its numeral form, not word form:

312 base pairs

2. Use the numeral form when comparing with numbers:

A total of 5 out of 24 of the respondents dropped out of the study.

NOT: A total of five out of twenty four of the respondents dropped out of the study.

3. Do not begin a sentence with a digit; instead use the word form for the number in question, even if it is above eleven:

Fifty-six rats were used.

NOT: 56 rats were used.

Or rewrite the sentence instead of beginning with a lengthy word:

A total of 4,589 moths were collected.

NOT: Four thousand five hundred eighty-nine moths were collected.

4. Separate every three digits with a comma, except with numbers after a decimal. Use a period as a decimal point, and not a comma:

3,000 participants completed the survey.

NOT: 3.000 participants completed the survey.

5. Be careful with compound nouns that report numbers. All words preceding the head noun must be singular since they function like adjectives. In English, adjectives are always singular:

A 36-day-old rat.

NOT: a 36 days old rat.

6. The terms twice vs. two times have essentially the same meaning, except that twice might be favored for being shorter.

The specimens were disrupted by sonication two times for 45 s at 5°C.

The specimens were disrupted by sonication twice for 45 s at 5°C.

7. The term circa is used with historical dates, but not typically with measurements. Likewise, the symbol, “” means approximately. Only use it in math applications, not in prose. Instead, use the word “approximately” in running text:

The temple was destroyed circa 1432 BCE.

Approximately 542 birds were sighted.

NOT: Circa 542 birds were sighted.

Approximately 2ml was added to the buffer.

NOT: Circa 2ml was added to the buffer.

The temperature was approximately 35C

NOT: The temperature was “” 35

8. Avoid imprecise expressions such as a 3-fold rise, 2-fold increase, two times as much , but instead use a more precise numerical percentage or decimal point when reporting precise quantities. This form can be used in a context where an approximation is acceptable, yet the number form should be used, not the word form:

3-fold increase NOT: threefold increase

9. When describing a decade use this form:

In the 1970s

During the 1980s

NOT: In the 70’s

NOT: In the Seventies

NOT: I n the 70s

10. Ordinals are commonly used in English to focus on rank, order or a sequence of certain quantitative data. They can be represented in numerical form or word form; for example, 1st, 2nd, 3rd, 4th, first, second third, and fourth. Do not confuse their form:

Eleventh, twelfth, thirteenth,…

NOT: eleventeen, twelveteen,…

As the CSE points out, “Ordinal numbers generally convey rank order, not quantity. Rather than being expressly enumerative (answering the question “How many?”), ordinals often describe “which”, “what”, or “in what sequence”. Because this function of ordinals is more prose-oriented than quantitative, distinctiveness within the text is less important for ordinal numbers, and undisrupted reading flow and comprehension take precedence”. Hence use the word form for ordinal numbers under 10:

The second wave toppled the wall.

The third sample contained only sediment.

The ninth patient quit the study due to family issues.

Use the numeric form for larger numbers above 10 as the word forms can be lengthy and awkward:

The 15th attempt was successful.

The 25th test was incomplete.

We focused on the 19th century.

The 97th test run

NOT: The ninety-seventh test run

The 21st Century

NOT: twenty-first Century

The numeric form can be used for numbers under 10 if they referred to repeatedly:

We surveyed 8 subjects: the 1st was most coherent, the 3rd, 4th, and 6th were contradictory, while the 5th, 7th, and 8th were moderately coherent; yet t he 1st could not recall the incident, and the 6th and 8th provided highly specific details of certain events.

Do not use an ordinal when writing the complete date:

February 7, 2014.

NOT: February 7th, 2014.

Use the short numerical form rather than the longer word form when discussing centuries:

Then 19thCentury

NOT: The nineteenth Century

11. Use the percent symbol (%) whenever a numeral accompanies it. Also, use no space between the number and the percent symbol:

NOT: 0.053 percent

NOT: 0.053 %

12. When two numbers are adjacent, for the sake of readability, spell out one and leave the other as a numerical form:

As shown in Table 2, three were not recovered.

NOT: As shown in Table 2, 3 were not recovered.

13. In running text in general, fractions should be represented in word form, rather than numerals. All two-word fractions should be hyphenated, whether as a noun or adjective form.

Roughly one-tenth of the study subjects reported adverse effects.

Two-thirds of this species is found in Brazil.

Nearly three-quarters of the respondents were pleased with the outcome .

Yet, for fraction quantities greater than one, use mixed fractions when you do not intend to give a precise value:

The study site was approximately 3¾ kilometers from the river.

The study ran for about 2½ years.

When a more precise value is desired, use a percentage or decimal form of the number.For mixed numbers with built up fractions, place the whole number close to the fraction, but for solid fractions, place a space between the whole number and the fraction:

Built up fraction: 9

Solid fractions: 9 2/3

14. With numbers that are less than 1.0, use an initial zero to the left of the decimal point:

0.345 NOT: .345

NOT: P = .05

15. When reporting quantities, consider what unit of measurement and decimal place is most meaningful to report. Round numbers to the most relevant and meaningful digit. For example, while reporting the average length of a group of fish, reporting centimeters would be the most meaningful unit to report. For example, it would be meaningful to report an average length of fish as 12 cm, and it might even be meaningful to report the tenths of Cen termers as in 12.4 cm, yet it would not be necessary to report in hundreds 12.37 cm or thousands of centimeters as in 12.372 cm. Reporting too many decimal points can be distracting to the reader and have little scientific importance. For example, note how it is easy to grasp the general pattern of weight gain in the following two sentences:

We noticed an average weight gain of 14.4529 g for college students, 12.39815 g for retired couples and 2.99277 g for single parents.

We noticed an average weight gain of 14 g for college students, 12 g for retired couples and 3g for single parents.

16. When reporting percentages, if the sample you are considering is less than 100, then round to whole numbers. With samples larger than 100, it could be meaningful to report one decimal point. Yet, consider how it will improve the readability and importance of the number. Note this pattern in the sentences below:

Of the 23 students studied, 32% (7 students) reacted favorably, 49% (11 students) had a neutral response, and 19% (4 students) had an adverse reaction to the practice.

NOT: Of the 23 students studied, 32.432% (7 students) reacted favorably, 48.983% (11 students) had a neutral response, and 18.594% (4 students) had an adverse reaction to the practice.

17. In research papers, numbers typically combine with units of measure or symbols, as specified and defined by the International System of Units (Système International d’Unités). These symbols can be alphabetical ( e.g., kg, μg, K, mol, A, s, Hz, mm, mL, min, g, cm) or non-alphabetical (e.g., $, %, S, £, °, ¹). As a general rule, numerals should always accompany these symbols:

A 25.0 mL  aliquot of 0.25 M HCNO (weak acid) is titrated with 0.15 M NaOH.

Near lead smelters and battery plants, air levels typically ranged from 0.3 to 4.0 μg/m3

18. Separate symbols from numbers with a single space:

19. Close up the space between a non alphabetical symbol and a number:

Note, one exception to this rule: The Council of Scientific Editors recommend a space here, while the American Medical Association recommends no space:

CSE Style: 45 °C

AMA Style: 45°C

Ultimately, you will need to follow the style guide recommendations from the journal that you planning to submit your research paper to.

21. When representing numbers in a range, use the word “to” between numbers, and not a hyphen or a dash:

Regional unemployment rates ranged from 1.2% to 33.3%.

NOT: Regional unemployment rates ranged from 1.2% - 33.3%.

When using the preposition “between” to introduce a range, always accompany it with “and”, not a hyphen or a dash:

In a range between 4 and 10cm.

NOT: In a range between 4 - 10cm.

When the range includes numbers with several digits, do not leave out the leading numbers of the second number of the range:

1958 to 1962

NOT: 1958 to 62

1,724 to 1,736

NOT: 1,724 to 36

You can use a single unit symbol alone after second number in a range of numbers, except for when the symbol is non-alphabetical and must be closed up to the number (e.g., $,%).

30 to 45 mL

120 to 200 Hz

10 to 20 min

NOT: 40 to $60

NOT: 13 to 22%

Be careful when expressing a change in value in a range, especially when using terms like “increased”, “decreased” or “changed”. Use language that clarifies that the change is in the range or in the final amount.

Growth increased by a range of 1.5 g/d to 3.5 g/d.

Growth increased from an initial value a range of 1.5 g/d to a final value of 3.5 g/d.

NOT: Growth increased by 1.5 g/d to 3.5 g/d.

NOT: Growth increased from 1.5 g/d to 3.5 g/d.

22. When reporting dimensions, use a multiplication symbol and not the letter “x” or the word “by”, and leave a space between the multiplication symbol and the numbers:

NOT: 22 by 18 by 16

When the focus is on expressing one range changing to a new range, place a hyphen between numbers to improve readability:

increased from 25–34 mm to 28–42 mm 

NOT:  increased from 25 to 34 mm to 28 to 42 mm

23. For a series of numbers, place the symbol after the last number, except in cases where the symbol must be close to a number:

14, 15, 18, and 54 Hz

$21, $37, and $41

10%, 14% and 34%

24. Express large numbers or very small number in powers of 10, scientific notation.

NOT: 38,000

NOT: 735,000,000

NOT: 0.000,003,51

25. For large numbers that are not expressing high precision, a combination of numbers and words are acceptable:

The population is around 25 million.

NOT: The population is around 25, 000, 000.

26. With common symbols of math operations ( separate the symbol and number with a space or thin space. Use the math symbol and not the letter x to represent multiplication. Do not use these sybmols in running text:

The averages equaled the total of all samples from plot A plus plot B.

NOT: The averages = the total of all samples from plot A + plot B.

When these symbols are used as modifiers of words, then close up the space between them and the term they modify. Also, do not place two or more operator symbols side by side.

Also, do not place two or more operator symbols side by side.

The total was greater than

NOT: The total was

27. For symbols used in calculus, refer to the Association of American Publishers for extensive details directions on their markup in manuscripts. For details on how to present vectors, scalars, tensors, matrices and determinants, see Scientific Style & Format: The Council of Scientific Editors, Chapter 12.

28. Brackets, parentheses, and braces in mathematics are referred to as enclosures or “fences”. In math, their order of use is parentheses within brackets within braces, and the reverse is order follows in non-mathematical prose: braces within brackets within parentheses.

mathematics: { [ ( ) ] }

prose or non-mathematics: ( [ {} ] )

29. In the following math expressions no space (closed up to the number) is required:

When expressing multiplication without the multiplication symbol:

Between fences and enclosures and the variables on either side of them:

(2p − 6bc)(1 − a)

 Between terms and their subscripts as in the following terms:

With the symbols plus and minus when used to indicate positive or negative value for numbers:

When expressing a ratio using a colon, close up the space:

Place a space between all common math operators: +, =, -,

30. Ratios, percentages, and proportions are commonly used to simplify and report research findings. Whenever using them, be sure to report a numerator and denominator of that accompanies them; otherwise it will be difficult to interpret them in a meaningful way. For instance 50% could be 2 of 4 samples had a positive result or 6,000 of 12,000 had a positive result. While both are examples of 50%, they would have a very different meaning in research. Separate the two numbers of a ratio by a colon, with the first typically being the numerator and the second the denominator:

The ratio of negative results was 3 to1 (946:329).

NOT: The ratio of negative results was 3 to1.

Proportions are the result of dividing the numerator by the denominator, with the numerator typically a subset of the items in the denominator:

The proportion of subjects experiencing adverse effects was 0.032 (21/651).

NOT: The proportion of subjects experiencing adverse effects was 0.032 .

To express a proportion as a percentage, multiply it by 100.

The percentage of subjects experiencing adverse effects 3.2% (21/651).

NOT: The percentage of subjects experiencing adverse effects 3.2% (21/651).

After studying the points made above about presenting numbers, correct the sentences below with errors related to numbers.

1. 4 assays were performed.

2. Measurements were made for just about one hundred and fifty snakes.

3. Since 80ies’ it has been shown that X plays a role in Y.

4. The 2th and 3th samples were negative.

5. This accounted for most of the total biomass.

6. Many informations can be found in the literature.

7. A lot of water was needed.

8. The deprotonated ion increased by about 2-fold.

9. For this case, the factor was just about 0.90, i.e. very close to one.

10. Three of percent of the samples were positive.

11. Each stock was valued at ten thousands of dollars.

12. Circa 10 mM was used.

13. 17x4=68

15. The total was

16. The population is around 25, 000, 000.

17. We found 15 % similarity.

18. The range increased from 25 to 34 mm to 28 to 42 mm.

19. As shown in table 3, 2 there was a significant increase.

20. The average cost per sample was 40 to $60

21. As many as 13 to 22% of the participants expreienced no adverse effect.

22. One tenth of the subjects reported improved vision.

23. We detected a difference of 0.000,003,51.

24. Statistical significance was set at .05

25. Rates ranged from 1.2% to 33.3%.

Check Answers Below:

Four assays were performed. Begin a sentence with the word form (four), not a digit (4). Measurements were taken for approximately 150 snakes. Since the 1980sit has been shown that X causes Y. The 2nd and 3rd were negative for… …Accounted for the majority of the biomass.a great deal of informationcan be found in the literature.A great deal of water was needed. Give a precise numerical percentage rather than something vague like “about 2-fold”.Avoid vague and informal term such as “just about” and “very close to”. Instead substitute “approximately” and “nearly”. Three percent of the samples were positive. Each stock was valued at ten-thousand dollars Approximately10 mM was used. (Use space between common math operators) 94 (use no space between numeral and exponent)The total was greater than (Avoid presenting two math operator symbols side by side).The population is around 25 million. (Use the word form when giving large imprecise numbers).We found 15% similarity. (No space between numerals and non-alphabetical symbols).The range increased from 25–34 mm to 28–42 mm. (When reporting a change of ranges, use a hyphen between numbers to improve readability).As shown in Table 3, three subjects dropped out. (When two numbers are adjacent, for the sake of readability, spell out one and leave the other as a numerical form).

20. The average cost per sample was $40 to $60 (When presenting a range, both numbers must be accompanied by the non-alphabetical symbol).

21. As many as 13% to 22% of the participants experienced no adverse effect. (When presenting a range, both numbers must be accompanied by the non-alphabetical symbol).

22. One-tenth of the subjects reported improved vision (hyphenate two-word fractions).

23. We detected a difference of 3.51 ´ 10-6 (write out very large or very small numbers in scientific notation)

24. Statistical significance was set at 0.05 (Place a zero before a decimal place.

25. Rates ranged from 1.2% to 33.3%. (Use the preposition “to” between numbers in a range, not a hyphen).

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Using Numbers in Scientific Manuscripts

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When should you spell out a number in a scientific paper, and when do you use a numeral? Here's how to follow conventions and be consistent.

Updated on January 8, 2013

Writing a scholarly manuscript often requires the use of numbers to express important information, particularly in the sciences. Although the use of numbers is largely straightforward, there are a few things to keep in mind. In this article, numeral refers specifically to a number as it is written in mathematics (e.g., 4).

Do not start a sentence with a numeral

When writing for publication, try to use spelled-out numbers at the beginning of a sentence in place of numerals. This distinction is not based on grammar, but rather the conventions of academic writing in English.

• " 15 samples were collected " should be written as " Fifteen samples were collected "
• At times, writing out the numeral at the beginning of the sentence would be particularly unwieldy. In such cases, it is preferable to rearrange the sentence such that the numeral is not placed at the beginning. For example, " 6579 patient charts were collected for analysis " could be altered to " Charts from 6579 patients were collected for analysis "
• Note that some chemical compounds include numerals, and these should not be written out, even at the beginning of a sentence: " 5 -hydroxytryptamine is a neurotransmitter derived from tryptophan. "

Be consistent in the use of numerals or spelled-out numbers

Other tips for number usage involve consistency within your manuscript. As shown above, each number can be written as a numeral or a word. Many authors choose to use numerals for large numbers (say, those over 10) but words for small numbers. Either form is typically fine, but it is best to be consistent with your choice.

• If " We collected a total of eight samples " is written in your Methods section, avoid writing " Samples from all 8 lakes were nearly identical in pH " in your Results. Either correct the first sentence to include a numeral ('8') or change the second to the spelled-out word 'eight.'
• In addition, try to avoid mixing numerals and spelled-out words within a single sentence. For example, we suggest changing " The zoo has two pandas, eight elephants, and 15 orangutans " to " The zoo has two pandas, eight elephants, and fifteen orangutans ."

Other tips for consistency with numerals

Here are two other ways to make sure that your numerals are consistent within your manuscript. Consistency in your formatting choices is one way to demonstrate your attention to detail. Always consult your target journal's style sheet to see what they prefer.

• When using numbers larger than 1000, be sure to format them all in the same way. For example, 156000 , 156,000 , and 156 000 are all acceptable, but use only one format in your document.
• Be consistent with the inclusion or omission of a leading zero before decimals (i.e., 0.05 or .05 , but not both). Also, do not mix the use of a decimal point (0.12) with a decimal comma (0,12). In the vast majority of cases, journals prefer the use of the decimal point.

We hope that this article provides some guidance for the use of numbers in your writing. If you have specific questions about the numbers in your text, write to us by email at [email protected] . As always, AJE wishes you the best of luck with your research and publication!

Ben Mudrak, PhD

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Numbers in APA

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In general, APA style recommends using words to express numbers below 10, and using numerals when expressing numbers 10 and above. See below for a more extensive list.

Numbers expressed as numerals

In addition to expressing numbers 10 and above, the following are other instances when you would use numerals rather than words:

Numbers mentioned in the abstract, a table, or a figure in the paper (this allows for brevity) 

This study consisted of 8 tests.

Numbers that immediately precede a unit of measurement

2.54 cm, 1.5 gal

Numbers that represent statistical or mathematical functions, fractional or decimal quantities, percentages, ratios, percentiles, and quartiles

Divided by 10

50% of the participants

a ratio of 10:1

the 10 th percentile

numbers that represent time, dates, ages, scores and point values on a scale, exact sums of money, and numerals

2 hr 30 min

50-year-olds

A 10-point scale

Exception: Use words for approximations of numbers of days, weeks, months, or years

Roughly six months ago

Numbers that denote a specific place in a numbered series, parts of books and tables, and each number in a list of four or more numbers

Illustration 1

Numbers expressed as words

In addition to using words to express numbers below 10, use words to also express:

Numbers beginning a sentence, title, or text heading

Fifteen participants were in the control group.

Common fractions

Three fourths of the population

Common phrases or groups

Seven Wonders of the World

The Three Musketeers

Other Rules Concerning Numbers

Here are a few more rules concerning numbers to adhere to as you follow APA style:

If you are using two modifiers against a noun, use a combination of both numerals and words

Three 5-point scales

If you’re unsure which modifier to write and which to express numerically, try it both ways. Be sure the way you express the numbers is in the clearest way possible.

Place a zero before a decimal fraction less than 1 if the statistic can exceed 1.

If the statistic cannot exceed 1, you do not need a zero.

For more specific guidelines, talk to your instructor or refer to the Style Manual.

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Numbers In Academic Writing – APA Style Guidelines

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Numbers are an imperative part of academic writing , serving as vital tools to represent quantitative data, statistical data, or measures in an accurate and precise manner. Numbers are used across various fields, including sciences, humanities, and business. However, adherence to specific rules is necessary in terms of using numbers effectively in academia, which vary depending on the style guide followed. This article will provide insights into how numbers are used appropriately.

Inhaltsverzeichnis

• 1 Numbers in Academic Writing – In a Nutshell
• 2 Definition: Numbers in academic writing
• 3 Numbers in academic writing: Exceptions
• 4 Numbers in academic writing: Percentages
• 5 Numbers in academic writing: Statistical results
• 6 Numbers in academic writing: Measurements
• 7 Numbers in academic writing: Long numbers

Numbers in Academic Writing – In a Nutshell

• Academic writing uses numbers in distinct ways depending on style guide.
• Conventions apply to technical number writing and non-technical number writing.
• Numbers are usually written out from one to nine, and numerals are used from 10.
• Technical data and statistics should always appear as numerals for reference.

Definition: Numbers in academic writing

The APA Style is one of the most widely used academic writing styles and is largely adopted by the behavioral and social sciences. A number can be written both numerically or in words within this style.

Typically, a number from one to nine should be written out as words, while numbers from 10 and above should be written out numerically. This general rule also applies to ordinals (first, 10th). Some exceptions do apply, as found next in this article.

Other writing styles utilize different number rules. The Chicago style , for instance, requires numbers to be written out as words up to 100. The MLA style spells out all numbers that can be written within one or two words (three, one hundred, etc.).

Numbers in academic writing: Exceptions

Exceptions to the general rule above apply in the following cases:

1. All numbers should be represented numerically when they are detailing an exact unit of measurement.

• The rock was chiseled 6 cm deep.

2. Write out numerals as words when they begin a sentence, except when dealing with specific years.

• Eighteenth-century scientists advanced the practice of medicine
• 1921 marked the discovery of insulin.

3. A number should be written out when dealing with fractions, set expressions, or other known numeric titles.

• John Milton crafted the poem in 1626, also referred to as the Fifth of November poem.
• According to sources, one-third of the English population perished from the Black Death.
• Orwell’s Nineteen Eighty-Four is set in an alternative world in the year 1984 .

Numbers in academic writing: Percentages

When dealing with percentages in the APA Style, use numerals followed by the percent sign % , instead of “percent” or the abbreviations, “pct.”, “pct,”, or “pc”.

• The Spanish flu affected over 25% of the US population.

The same rule when beginning sentences with numerals applies to percentages, i.e., they should be written out as words when they start a sentence.

• Twenty-five percent of the US population was affected.

Numbers in academic writing: Statistical results

Reporting statistics in APA and papers that deal with technical numerical language in qualitative research have their own rules.

Here, all data is written in numerals to remain consistent and easily digested. This applies to the main body, tables, and figures sections of a paper.

Other statistical conventions include:

• Report the majority of statistics to two decimal places.
• Report statistics that can’t exceed 1.0 to three decimal places.
• For values that could exceed 1.0, use a leading zero. Those that can’t exceed 1.0 do not feature a leading zero.
• Italicize statistical values that aren’t Greek letters. E.g. SD .
• Spaces should be left before and after equal, more-than, and less-than signs.

Numbers in academic writing: Measurements

Always use numerals for units of measurement.

• Ampules contain 100 mg in 2 ml .

Numerals should be used for precise ages, timescales, dates, score lines, points of scale, and monetary sums.

• The final score was France 4 , and Croatia 2 .
• The students were aged 18 to 21 years in the study.

Imprecise ages and generalizations are not numbered but written out.

• She was roughly six years old based on his estimation.
• The outcome will be approximately seven times .

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Numbers in academic writing: Long numbers

Longer numbers have their own set of rules. A period should be used to indicate a decimal point.

Commas are to be used to separate large figures every three digits after 1,000.

For sums exceeding 6 numerals, like 1 million and 1 billion, use a combination of numerals and written language.

• HBO Max had 73.8 million subscribers in 2022.
• This is a considerable growth from its 800,000 subscribers in 2015.

Should you write out numbers in academic writing?

As a general rule of thumb, numbers up to nine should be written out in the APA Style, while anything exceeding 10 should appear as numerals.

How are dates written in academic writing?

Dates are always written as numerals.

How are numbers expressed at the beginning of a sentence?

They are written out when they begin a sentence, except for dates and technical data.

Should I use the word "percent" or its symbol "%"?

The APA Style states that the symbol “%” should be used after numerals, while “percent” should be used for written-out figures.

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