So often teachers of subjects other than language arts report that one reason they don't require much writing is because they are unfamiliar and uncomfortable with some of the finer points of grammar and usage. We did a couple of quick little exercises in my Writing Across the Curriculum workshop today where the objective was to show that that type of incorrectness does not usually impede communication and also that those errors are usually the easiest thing to fix in a writing piece. One task the participants had to do was choose between "fewer" and "less" when the terms were applied to the word "people," as in There were fewer/less people at the park than there were at the movies.
The rule with "fewer" or "less" is countability-- you use "fewer" when you can count the individual items and "less" when you can't, like fewer pennies, less change. The tricky part of the above question is that "people" was not originally used as the plural of "person" (that would have been "persons"), so there was a time when you couldn't actually count the people in a room, and therefore "less people" was the correct usage.
Today that is not the case, people is the commonly accepted plural form of person. The topic certainly made for a lively discussion in our session today, though, and who do you think brought it up?
The math teachers, of course. Count on them!