Which of the following is true?
A. 5 is a prime number becuase one and five are its only factors
B. 19 is a composite number because it is only divisable by one and itself
C. 12 is a prime number because it is divisable by 4
D. 25 is a composite number because 52 is a prime number

Question

Which of the following is true? 
A. 5 is a prime number becuase one and five are its only factors 
B. 19 is a composite number because it is only divisable by one and itself
C. 12 is a prime number because it is divisable by 4 
D. 25 is a composite number because 52 is a prime number

zehanz · Answer

To be able to answer this question (and others about prime numbers) it is important you know exactly what is meant by a prime number.
This means you have to learn the definition of a prime number, it is not enough to have only a vague idea what prime numbers are (like "numbers as 3, 5, 7 11 etc.")

Do you know the definition of a prime number?

anonymous · Answer

um A Prime Number can be divided evenly only by 1, or itself. 
like  5 can only be divided evenly by 1 or 5, so it is a prime number.
But 6 can be divided evenly by 1, 2, 3 and 6 so it is NOT a prime number (it is a composite number).  right?