BK Blog Post
Posted by
Jeevan Sivasubramaniam,
Vice President, Editorial,
Berrett-Koehler Publishers Inc.
"Fewer" is used when you're talking about an actual number of things and is only used with plural nouns.
Example: Fewer adults floss daily than they did 20 years ago. (Adults is a plural noun.)
"Less" is used when the amount is undefined and is only used with singular nouns.
Example: Less than half of adults floss daily. (Half is a singular noun)