This is the third in a series of posts to address common issues I have found in manuscripts with my suggestions for how to improve manuscripts before turning them over to agents, editors, and the many other individuals involved in the process of turning a manuscript into a book.
#3 Writing out numbers vs using numerals
The Chicago Manual of Style (CMS) offers two principles to determine when numbers should be spelled out and when numerals should be used. The general rule requires spelling out all numbers from zero to one hundred. The alternative rule requires spelling out numbers from zero through nine. This applies to ordinal variants such as first, second, third, and so on.
In general, when editing the works of others, I follow the first general rule in novels and the alternative rule for short stories or other short pieces.
But, CMS recommends different approaches in certain instances.
When including percentages, CMS recommends using the numerals with the spelled out word percent (Section 9.18 in the 16th edition). See the example below.
The U.S. current account deficit widened by $17.2 billion, or 10.6 percent, to $178.5 billion in the third quarter of 2020, according to statistics released by the U.S. Bureau of Economic Analysis. The revised second quarter deficit was $161.4 billion. The third quarter deficit was 3.4 percent of current dollar gross domestic product, up from 3.3 percent in the second quarter.See Bureau of Economic analysis website
CMS provides an exception to that rule as well. The text of Section 9.18 in the 16th CMS edition begins, “Except at the beginning of a sentence . . .” since CMS advises numerals should not begin sentences.
The example above also illustrates the second CMS exception under certain circumstances, which allows for violating the general principles for the sake of consistency and flexibility. If a pargraph would otherwise include both numerals and spelled out numbers, follow the same pattern throughout each category of numbers. In the example above, the dollar values are represented by numerals, but references to the economic quarter, third, follows the general rule because the quarters and dollars are different categories.
In all cases, consider the reader and what would make it easier to understand. In many cases, numbers in a graph or chart simplify the readers’ task. The same BEA website includes many examples of charts and graphs.
The bottom line: The manuscript should be easy for the reader. If following the rules makes reading harder, break the rule as needed.