Deciding how to express numbers in your writing can be confusing. Especially since there’s no consensus on what’s right and what’s wrong. There are some basic rules that are fairly universal, but there are others that many writers disagree on.
The best way to express numbers in your writing is to stick to the basic rules, use your own personal logic, and remain consistent in all your writings. With that being said, here are some basic rules for deciding when to use numeral and when to write the numbers out.
Spell out small numbers
Some people will tell you to write out numbers all the way up to 100. However, it’s not necessary. I prefer to write out numbers only up to twenty. Numbers that are less than 21 are easy to write because you don’t have to use hyphens. Who would prefer to write eighty-seven when 87 is so much easier? Not me!
Don’t start sentences with numerals
Numerals are the symbols that we use for number (e.g., 7, 61, 103). You should never start a sentence with a numeral. This may contradict the previous rule, but it’s necessary. Instead of starting your sentence with “35 people won the lottery” you should say “Thirty-five people won the lottery.”
Always spell out centuries and decades
Instead of saying the 60’s or the 20th century you should write it out. For example, “The sixties was known for rock-n-roll” or “The twentieth century made huge technological advances.”
Use numeral and words for big numbers
Let’s say you decide to use numeral starting at 21. That means you’ll always use numerals for numbers like 99, 515, 800, 1,600, 73,000, and 429,000. That’s fine. But when you start getting into the millions and billions, it’s much better to write 80 million instead of 80,000,000.
Don’t put two numbers next to each other
This rule has more to do with the reader than it does with the writer. In order to make your writing easier to understand, avoid putting to separate numbers next to each other. For example, “35 15-year-old students are on the bus” is better expressed as “thirty-five 15-year-old students…”
These are just some of the many rules there are to writing numbers. The most important thing to remember is that once you pick a style, try to stick with it throughout the entirety of your writing. It’ll make things a lot easier for you and the reader.