Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
Fifty is regular. It follows the -ies Conversion rule.
Use plural verbs: "The fifties are ready" (not "is ready").
Yes. The plural fifties is standard across all English variants.
The word fifty follows the standard English pluralization rule. When forming the plural, fifty becomes fifties. This follows the -ies Conversion pattern, which is one of the most common plural rules in English.
Understanding why fifty becomes fifties helps with spelling and pronunciation. Nouns ending in a consonant followed by -y change the -y to -ies in the plural form.
When using fifties in writing, remember that it functions as a plural noun in sentences. It pairs with plural verbs and pronouns. For example: "The fifties are ready" (not "is ready"). This subject-verb agreement is essential for grammatical correctness.