Section 9.5

Numbers

Unless you are following a style guide thatspecifies otherwise, observe the following guidelines in usingnumbers.

• In general, use arabic numerals instead of words in scientific and technical writing for both cardinal and ordinal numbers:

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3 subroutines	6 braces	61 amino acids
the 3rd subroutine	the 6th brace	the 61st amino acid

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• In some scientific and technical styles, however, write out numbers between one and ten and two-word fractions that do not follow an integer:

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three subroutines	six braces	61 amino acids
1½ hours	one-half hour

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• If you need to begin a sentence with a number, spell it out. It is better, however, to reword the sentence, if possible.

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Thirty-two workstations were provided by theuniversity.

The university provided 32workstations.

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• If one number immediately follows another in a sentence, spell out the one that can be expressed in fewer words. Try, however, to express units of measure in arabic numerals. Another solution is to reword the sentence.

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We then prepared eight 20 mlsamples.

We then prepared 8 samples of20 ml each.

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• Always spell out the pronoun one:

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In protecting the privacy of individuals,one must always consider all the possible waysdata can be accessed and used.

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• Use numerals for dates, time of day, pages, figures, and notes:

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5 August 1994

1 p.m.

page 43

Ref. 6

Figure 43

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• Use arabic numerals followed by the percent sign, (%), to express percentages, except when the number begins a sentence:

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Only 3% of the systems crashed during thetest period.

Three percent of the systems crashed duringthe test period.

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British and American Formation of Numbers

• Form integers of two to four digits without any punctuation or spacing:

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21

412

8024

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• Use the period (.) to indicate the decimal point and use an initial zero (0) for numbers less than 1.0:

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  31.3

  1.41

  0.414

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• Form numbers of five digits or more by using a comma (,) to mark off groups of three digits, starting at the decimal point:

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10,000

12,341

12,341.34

12,432,421

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European and International Standards for Formation of Numbers

• Form integers of two to four digits without any punctuation or spacing:

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21

412

8024

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• Use the comma (,) to indicate the decimal point and use an initial zero (0) for numbers less than 1,0:

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31,3

1,41

0,414

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• Form numbers of five digits or more by using a period (.) to mark off groups of three digits, starting at the decimal point:

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10.000

12.341

12.341,34

12.432.421

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General Guidelines for Using Numbers in Nontechnical Prose

When using numbers in nonscientific text, spell out numbers lessthan one hundred or numbers of any size that begin a sentence. In addition, spell out round numbers of any size and use arabicnumerals followed by the terms million and billionto express numbers larger than one million.

146 billion

## Numbers ##


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