fewer, less, lesser

Fewer indicates plural number and is used with plural nouns.

• The Department of National Defence has bought fewer computers this year than last.
• Greater emphasis on health issues means that there are fewer people eating candy.
• The program benefits families with four or fewer children.
• Students must answer no fewer than 12 questions on the exam paper.

Less and lesser indicate a singular amount and are used with singular nouns (which are often uncountable).

• There will be one less participant in this competition.
• You will be assigned less work this week.
• Henk had even less money than I did in our student days.
• Granny used to joke that growing old was the lesser of two evils.
• I do enjoy cycling, but to a lesser degree than running.

Less is also used with plural measurements of distance, money, time, etc., which express overall amounts that are usually considered singular:

• Five kilometres is less than the distance I walked.
• Jean had less than $40 for groceries, so Carl lent her some money.
• We have less than twenty minutes to get ready!
• Can you express that in 25 words or less?

Less is also frequently used in mathematics to mean “smaller.”

• The sum of 7 plus 4 is less than 12.