Hi! I'm new here, so please be nice. I'm writing a book about (American) football. It's actually nonfiction, but I'm sure that's not a problem. Anyway, I have some questions about whether to use digits or to spell out the numbers, in other words, "9" or "nine." I've read that you're supposed to spell out numbers lower than 10, but I'm wondering if there are exceptions here. For example, "the running back picked up five yards on a 3rd-and-6." Is that right? Should I spell out 3rd? Should I spell out 6? Or should I make "five" into "5"? I want to be consistent, and this is a bit confusing for me. Any help you could give me would be appreciated, thank you.