alleryStart learning →The number 1 has only one factor, itself. Where does 1 fit among prime and composite numbers?
AIt is the smallest prime number
BIt is neither prime nor composite
CIt is the smallest composite number
DIt is both prime and composite
Answer & Solution
Correct answer: B. It is neither prime nor composite
1. A prime number needs exactly two different factors, 1 and itself, but for the number 1 those are the same factor.
2. A composite number is defined as a counting number that is not prime, yet 1 does not fit the prime definition either.
3. Because 1 fails both the prime test and the composite test, it is placed in a category of its own: neither prime nor composite.
_Source: OpenStax Prealgebra (CC BY 4.0), Ch 2 "The Language of Algebra", section 2.4 Find Multiples and Factors_
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