Grammar Nazi: Lesson 3
It's been over two years since Lesson 2, but I haven't forgotten about it. (And, sadly, I can only find Lesson 1, all the way back in June 2004.)
Lesson 3: How to Use "Less Than" and "Fewer Than" Properly
The rule is actually very simple: user "fewer" if the noun can be counted to a specific number, unless you're talking about time, money, or distance -- and even then, "fewer" is proper, but the linguistic powers that be have given in after decades of the incorrect usage pervading the language. See here.
In other words, you can have less than $20 in your wallet, but you have fewer than 20 one-dollar bills. The first instance references the value of money, while the second references the dollar bill as an object.
Lesson 3: How to Use "Less Than" and "Fewer Than" Properly
The rule is actually very simple: user "fewer" if the noun can be counted to a specific number, unless you're talking about time, money, or distance -- and even then, "fewer" is proper, but the linguistic powers that be have given in after decades of the incorrect usage pervading the language. See here.
In other words, you can have less than $20 in your wallet, but you have fewer than 20 one-dollar bills. The first instance references the value of money, while the second references the dollar bill as an object.