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Using Numbers, including Percentages
Style manuals do not agree on the issue of when writers should spell out numbers and when they should use numerals. And even a single style manual will point out that the guidelines change according to the type of number and the context in which it is being used.
Let’s begin with four points upon which everyone seems to agree:
First, we do not begin a sentence with a numeral. When spelling out a number would be awkward (as in “Two hundred seventy-five people attended the concert”), then it is best to rewrite the sentence to avoid having it begin with a number (“An intimate crowd of 275 people attended the concert”).
Second, a cluster of numbers in a sentence or paragraph is best handled with numerals for readability.
Third, numbers that refer to comparable quantities in close proximity should be treated the same. In the following sentence, for example, the number six is written as a numeral because the other two numbers in the same sentence are (in nontechnical writing) too complex to be expressed in words:
Attendance at the board meetings last year ranged from 6 people at the first meeting to 127 at the last, with the highest attendance being 237 when we discussed the budget.
Finally, decimal fractions and percentages should be expressed in numerals, not in words. We would write “The truck held 0.568 metric tons of steel” and “His approval rating increased 35 percent last week.”
Note, too, that the symbol for percent (%) should be used only in technical writing; in other contexts, we use numerals before the word percent, as in the example above.
The Chicago Manual of Style, our preferred guide, says that in nontechnical writing, we should spell out “whole numbers from one through one hundred, round numbers, and any number beginning a sentence” (380). Chicago provides an alternative for technical writers, which is to spell out “only single-digit numbers.” The authors point out, though, that such rules “should be used with flexibility so as to avoid such awkward locutions as ‘12 eggs, of which nine were laid yesterday’” (381).
Writers will want to avoid placing two numbers adjacent to one another to prevent a misreading. In such cases, it is helpful to spell out the smaller of the two numbers. For example, the phrase “10 9-inch nails” would be better written as “10 nine-inch nails.”
TEST YOURSELF: Assuming that the following sentences were written for use in nontechnical contexts, can you spot errors in the use of numbers?
- 386 people were forced to evacuate to shelters during the hurricane.
- Our library holds three thousand nine hundred sixty-four volumes on health-related issues.
- The movers claim that the contents of our office weighed three point two tons.
- Through a rigorous training program, she reduced her body fat to 12%.
- The hurricane forced the evacuation of 386 people to shelters.
- Our library holds 3,964 volumes on health-related issues.
- The movers claim that the contents of our office weighed 3.2 tons.
- Through a rigorous training program, she reduced her body fat to 12 percent.
Copyright 2003 Get It Write. Revised 2018.