A simple rule for utilizing numbers in writing is to spell out little numbers ranging from one to ten (or one to nine, depending on the style guide). Larger numbers (those more than 10) are written as numerals. Professional numbers include dates, times, phone numbers, addresses, and email messages. They are always spelled out in full, with no abbreviations. January 1st, 2037 at 8:30am. My birthday is January 1st, 2037. I'm 25 years old. The number for poison control is 911. Phone numbers should be written out with area codes unless there's only one person involved, in which case they can be left off. I have a question about my health insurance. You can write numbers in sentences as long as they're not interrupting the flow of text too much. In this case, we included the date as well because it helps to identify what question we're answering. If you want to include your telephone number or address in an article or report, it's best to include the full address or phone number along with the relevant information such as "mailed to" or "written by hand." This will help those looking for information regarding these topics find them easily.