Fewer and less
Fewer is one of those words that seems to be disappearing. I don’t know if it is a case of ‘if in doubt, just use less’ or it’s because people simply forget that it exists. Fewer does fulfil a role that less does not, though, so if you want to get it right here is a basic explanation and some tips to help you.
Explanation of the difference:
Use fewer and fewer than when referring to discrete things that can be counted (countable nouns) – e.g. fewer people, children, days, coins, fields.
Use less and less than when referring to a singular or mass (uncountable) noun – e.g. less humanity, food, time, money, land.
Two tips to help you remember:
1) Remember a phrase like this – fewer facts; less learning.
2) Apply this test: if you can add a number directly in front of the word and the phrase makes sense – e.g. 5 gold rings – then you should use fewer or fewer than; if it does not make sense – e.g. 5 money – then use less or less than. (If you said 5 bags of money, you would use fewer because the 5 makes sense when placed directly in front of the words bags.)
Here is where it gets slightly more complicated:
Use less and less than when referring to a number on its own and with specified expressions of time, money or measurement – e.g. the journey took less than three hours; she had less than two pounds in her purse; he lost less than ten pounds in weight.
A final tip:
3) Remember a phrase like this: less than two hours’ revision = fewer facts + less learning.