When you dial a phone number, it includes several pieces: the exit code, country code, area code, and telephone prefix. The area code identifies the broad region in which you’re calling, and the telephone prefix is a smaller area within that region.
In the past, these parts were often separated by words, called “exchange names.” You’ll see a lot of them in old movies and TV shows. But when the numbers were standardized, it removed a lot of them.
Location
If you want to locate a phone number that you’ve seen on a bill, you can try one of several free online databases. Many of them will also allow you to find out what telephone company services that location. You can search for a location by entering its area code and exchange number. A map will appear, revealing the name of the location along with its associated telephone company. You can usually also input a country into the search box, which will help to validate the number against a specific country’s rules and format. However, you can leave this field empty if you don’t know the country. Alternatively, you can search by area code only. The results are returned in the form of a json object.
Numbers with a hyphen
When you exchange phone numbers, it’s a good idea to follow standard formats. This will reduce clutter and make the number more readable.
For North American numbers, enclose the area code in parentheses and hyphenate the three-digit exchange code with the four-digit number. In other countries, omit the area code and place it in brackets.
You’ll also need to hyphenate all numbers between 21 and 99 (less those ending 0). These are called en dashes, which is the length of a lower-case n.
You should also hyphenate all fractions, whether they’re whole numbers or numerals. But only use them when the fraction is an adjective or adverb before a noun, as in They got a one-third share or The money is three-quarters gone.
Numbers with a dash
When using numbers in writing, a dash is an essential punctuation mark. It helps readers understand the number, and signals a difference or range.
There are several types of dashes that you should know about. These include the en dash and the em dash.
The en dash is the shorter of the two and is most often used to indicate a range in numbers. It can also be used to show differences between numbers, like a difference between two dates or different times on the same day.
If you’re unsure about the correct way to write numbers, look at a style guide. They’re usually for a specific type of writing, and will have their own rules about how to use numbers.
For example, the European Commission’s style guide recommends an en dash with no spaces for percentage ranges, but this doesn’t always apply in other fields. In that case, it’s best to use the style guide that you prefer or are most comfortable with.
