When using degree of comparison, we refer to something having larger quantity or greater quality as ‘more.’ This applies to countable and uncountable nouns, which are represented by ‘many’ and ‘much,’ respectively.
In other words, we can use ‘more’ for both countable and uncountable nouns. This is not always the case with comparing two things with one having inferior quantity than the other.
By linguistic prescription/prescriptive grammar, or traditional grammar rules, so to say, ‘fewer’ is used with countable nouns and ‘less’ is used with uncountable nouns.
“There are fewer people living in this area now.” (‘people’ is a countable noun)
“I try to minimise deep-fried food, that’s why I use less cooking oil now than I used to.” (‘cooking oil’ is an uncountable noun)
When the uncountable nouns are presented with measurement units, we can go with both ‘fewer’ and ‘less,’ although in some cases, using ‘less’ sounds more natural.
“I drank less than 6 cups of water today. No wonder I felt tired.” (‘6 cups of water’ is a measurement unit)
‘Water’ is an uncountable noun, but in the example, it came with a measurement unit, which is ‘6 cups.’ Using ‘fewer’ is still correct, but it sounds less natural.
‘Less’ is also more generally acceptable to use with nouns that are intangible or inexplicit.
Forrest Gump said, “One less thing.”
Ariana Grande also sang, “One less problem.”
This is because ‘thing’ and ‘problem’ are still intangible; we don’t have enough information about how many ‘things’ or ‘problems’ the speakers are talking about. What we know is only the quantity of ‘thing’ and ‘problem’ has decreased.
All right, that’s quite a deep dive into the usage of ‘fewer’ and ‘less.’ Hope it helps.
#EngClass: Countable vs. Uncountable Noun
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#EngClass: Expressions of Quantity
#EngTrivia: Common Grammar Mistakes
#GrammarTrivia: Uncountable Noun