To determine whether a number is prime or composite, first recognize the definitions:
Prime Number: A number greater than 1 that has no divisors other than 1 and itself.
Composite Number: A number greater than 1 that has more than two divisors.
Let’s look at each number provided and verify their factors:
8:
Factors: 1, 2, 4, 8
Since 8 has more than two factors, it is a composite number.
25:
Factors: 1, 5, 25
Because 25 has more than two factors, it is a composite number.
21:
Factors: 1, 3, 7, 21
As it has more than two factors, 21 is a composite number.
30:
Factors: 1, 2, 3, 5, 6, 10, 15, 30
With multiple factors, 30 is a composite number.
5:
Factors: 1, 5
Since 5 has only two factors, it is a prime number.
48:
Factors: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
Given its multiple factors, 48 is a composite number.
19:
Factors: 1, 19
With just two factors, 19 is a prime number.
12:
Factors: 1, 2, 3, 4, 6, 12
As it has more than two factors, 12 is a composite number.
In summary, a number is classified based on its divisors: numbers with only two distinct divisors (1 and itself) are prime, while those with more than two divisors are composite.