I’m going to ease back into the blog with an easy topic: numbers. So when do you spell them out or put in the Arabic numerals (ex. 0, 1, 2, 3, etc.)? The simple guideline is when the figure is under 10 you spell it out while anything greater than 10 uses numerals. This also extend to sequences with first through ninth being spelled out, even in street addresses.
However as with all rules, there are exceptions, albeit it depends which style guide you or your publisher follow. One such exception is numerals cannot start sentences, so spell out numbers at the beginning of sentences even if a number greater than 10.
Estimates are spelled out as well, e.g. thousands turned out to see the show or approximately 400 thousand entered the dome over the course of five years. On the other hand, percentages, recipes and dimensions all get numerals. These are of course just some of the many rules, which might differ depending on the style guide used.
When in doubt, consult your style book. Don’t have a style book? Get one. The most common include: “The Chicago Manual of Style,” which is popular with many publishers, “The Associated Press Manual of Style,” “APA Style Handbook,” “MLA Handbook,” and of course the good and trusty, “Elements of Style” by William Strunk Jr.