Style Quiz #7: Basic Number Rules

By Mark Nichol

All but one of the following sentences demonstrate incorrect style for numbers according to The Chicago Manual of Style; revise the style of the number as necessary:

1. Last year, 37 aircraft were retired from the fleet.

2. The first time the class was offered, 245 students registered for seven sections, and 38 were put on a waiting list.

3. 157 cars were sold on the first day of the sale.

4. “Myriad” means “many,” but it also is specifically equivalent to 10,000.

5. One-hundred twenty-eight books are missing.

Answers and Explanations

Guidelines about styling numbers are complex, with exceptions for technical usage, large numbers, physical quantities, percentages and decimal fractions, money, times and dates, and so on, but the basic recommendations are simple.

1.
Original: Last year, 37 aircraft were retired from the fleet.
Correct : Last year, thirty-seven aircraft were retired from the fleet.

With some exceptions, numbers above one hundred should be in numeral form, and those below one hundred should be spelled out.

2.
Original: The first time the class was offered, 245 students registered for seven sections, and 38 were put on a waiting list.
Correct : The first time the class was offered, 245 students registered for seven sections, and 38 were put on a waiting list.

When listing numbers referring to the same thing or category of things (such as students, as in this example), use a consistent numeral style, but unrelated numbers should follow the basic style: This sentence is correct.

3.
Original: 157 cars were sold on the first day of the sale.
Correct : One hundred fifty-seven cars were sold on the first day of the sale.

Numerals should not begin a sentence; spell the number out, or recast the sentence (e.g., “On the first day of the sale, 157 cars were sold.”). Note that and should not separate the place values in a spelled-out number.

4.
Original: “Myriad” means “many,” but it also is specifically equivalent to 10,000.
Correct : “Myriad” means “many,” but it also is specifically equivalent to ten thousand.

In nontechnical contexts, and in the absence of precise numbers of more than two digits, format round numbers of three or more digits as words

5.
Original: One-hundred twenty-eight books are missing.
Correct : One hundred twenty-eight books are missing.

Hyphenate only the words for the tens and ones places.

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2 Responses to “Style Quiz #7: Basic Number Rules”

  • Dale A. Wood

    Oh, I disagree, disagree, disagree to the maximum degree.
    When it comes to numbers within text, “style” and related words have nothing to do with it. That does have to do with it are three things:
    A. Legibility, legibility, legibility!
    B. Accuracy, accuracy, accuracy!
    C. No quibbling about it.
    Many of these things date back to when people wrote mostly by hand, and also when LARGE numbers were rarely seen, and there has not really been any reason to change.
    One myriad is still 10,000.
    One million is still 1,000,000.
    One myriameter is still 10,000 meters, though this unit is seldom used.
    1,000 kilometers is still one megameter, is still 1,000,000 meters.
    One hectare is still 10,000 square meters.
    640 acres is still one square mile.
    36 square miles is still one township.
    The great Scottish mathematician John Napier popularized the use of the “.” as the decimal point. (He was the developer of the logarithm.) This “.” is still used in all of the English-speaking countries such as Britain, Ireland, Canada, the United States, Australia, New Zealand, South Africa, and also in French Canada and Spanish-speaking Mexico and Puerto Rico.
    This “.” is also used as the “binary point” by engineers and mathematicians. You can see a number in binary that looks like this: 101100010.11001 – where the thing in the middle is the “binary point”. The same idea works for octal numbers.

  • Dale A. Wood

    This ties in with an article in the near future about the words “quarter” and “quart”, and the subject of land surveying in most of the United States. There are exceptions in the older colonies that were settled along the Atlantic Coast, and in places that were first settled by Spanish colonists in Florida, Texas, and the Southwest, by the French in French Louisiana, and by the Americans in northeastern Ohio.
    In most of the rest of the USA, a township was defined as a square six miles by six miles (36 square miles), except in northeastern Ohio, where it was five miles by five miles (25 square miles). In either case, a section is one square mile, and one square mile is 640 acres.
    Each section contains four square quartersections of 640/4 = 160 acres, and in the Homestead Act of 1862, one quartersection was the land allocated to each homesteader who occupied and developed the land.
    In finer surveying, each quartersection was divided into four square quarter-quartersections of 40 acres apiece.
    Depending on the lay of the land and the way that water flowed, this lead to the terms “the upper 40” and “the lower 40”.
    Of course, in finer surveying, they got numerous quarter-quarter-quartersections of 10 acres apiece.
    They really liked to deal with factors of two and five, and
    640 = 2x2x2x2x2x2x2x5 .

    Also, in surveying over vast distances, periodic small corrections were made for the curvature of the Earth, and that got a little bit complicated.

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