Forty (40) is a cardinal number that can be grammatically classified as an adjective, noun, pronoun, or determiner. A cardinal number is used to indicate quantity.
Forty is sometimes misspelled as “fourty”—probably because 4 is spelled as “four”—but “fourty” is not a real word. This is also true when “forty” is used as part of a larger number, such as “forty-two” or “two-hundred-forty.” The QuillBot Grammar Checker will fix this and other common mistakes automatically.
Examples: Forty or fourty in a sentence ✗ My uncle will visit in fourty minutes.
✓ My uncle will visit in forty minutes.
“Forty” can be used as a noun to refer to the number 40, but it can also be used as a quantifier (determiner) to describe or modify another noun. It’s used as a pronoun to refer to previously mentioned nouns.
Examples: Forty in a sentence My grandparents have been married for forty years.
John ate twenty pretzels, and I ate forty!
Are you turning forty this year?
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