Do you hyphenate numbers?
Most (but not all) style books say to hyphenate numbers that have two words (e.g., “forty-six days”).
Unless your style requirements say otherwise, use a hyphen (-) when you need to write the words for a double-digit cardinal number (e.g., “thirty-one flavors”) or ordinal number (e.g., “twenty-first birthday”).
Some of the most common guidelines for hyphens and numbers are as follows:
- APA uses hyphens for two-word numbers but only uses words for 10 and greater at the beginning of a sentence (e.g., “Last year, 25 teachers retired” or “Twenty-five teachers retired last year”).
- Chicago uses words for numbers up to 100 and hyphens in numbers with two words (e.g., “The conference included workshops by twenty-seven professional musicians”).
- MLA requires words for all numbers that have one or two words and doesn’t use hyphens for numbers (e.g., “The researchers interviewed thirty two students”).
QuillBot’s free Grammar Checker can help you with hyphens, cardinal numbers, and more.