According to the amount of dividers, the numbers are classified as Prime numbers or compounds.
To do well in this matter, it is also important to know what are multiple and what are divisible numbers.
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Want to test your knowledge? Check out one of the following list of prime and composite numbers exercises.
The feedback for all of them will be available for you to check the answers.
Question 1. What is a prime number? A prime number is a number that:
a) has exactly two multiples, 1 and itself.
b) has exactly two divisors, zero and itself.
c) is divisible by exactly two numbers, 1 and itself.
Question 2. What is a composite number? A composite number is a number that:
a) has more than two divisors.
b) has more than two multiples, 1 being one of them.
c) has more than two divisors, zero being one of them.
Question 3. Regarding number 1, it is correct to say that:
a) is the smallest prime number that exists.
b) is the smallest composite number that exists.
c) is neither a prime nor a composite number.
Question 4. Regarding number 2, it is correct to state that:
a) is a composite number because it is divisible by 2.
b) is the only even natural number that is prime.
c) is a prime number because it is the smallest even number greater than 1.
Question 5. The largest prime number that exists is:
a) 997
b) it is not possible to determine the largest prime number.
c) 1000
Question 6. Regarding the multiples of a prime number, we can say that:
a) are exactly two.
b) are more than two.
c) are infinite.
Question 7. When we multiply a prime number by a composite number, we get a number as a result:
a) prime, because all multiples of a prime number are prime numbers too.
b) composite, because all divisors of the composite number will be divisors of the resulting number.
c) prime, as it will only be divisible by two numbers, those that we multiply.
Question 8. Knowing that 33 = 3. 11, we can say that 33:
a) is a prime number because it is the product of two prime numbers.
b) is a prime number because its only divisors are 3 and 11, which are prime numbers.
c) is a composite number, because it can be factored as the product of prime numbers, it will have more than two divisors.
Question 9. Knowing that 54 = 2. 3³, then we can state that:
a) 54 has only two prime divisors, 2 and 3.
b) The only divisors of 54 are 2 and 3, so 54 is a prime number.
c) 54 is a composite number because it is divisible by exactly three numbers: 1, 2, and 3.
Question 10. The number of prime divisors of 200 is:
a) 2
b) 5
c) 12
A prime number is a number that is divisible by exactly two numbers, 1 and itself.
Correct alternative: c
A composite number is a number that has more than two divisors.
Correct alternative: a
About the number 1, it is correct to say that it is neither a prime nor a composite number.
It is not prime because it has only one divisor, which is itself, and it is not composite because it has less than two divisors.
Correct alternative: c
About the number 2, it is correct to say that it is the only even natural number that is prime.
Correct alternative: b
It is not possible to determine the largest prime number.
Correct alternative: b
About the multiples of a prime number, we can say that they are infinite.
Correct alternative: c
When we multiply a prime number by a composite number, we obtain a composite number as a result, since all divisors of the composite number will be divisors of the resulting number.
Correct alternative: b
Knowing that 33 = 3. 11, we can say that 33 is a composite number, because it can be factored as the product of prime numbers, it will have more than two divisors.
Correct alternative: c
Knowing that 54 = 2. 3³, then we can say that 54 has only two prime divisors, 2 and 3.
Correct alternative: a
The number of prime divisors of 200 is 2, since 200 = 2³. 5².
Correct alternative: a
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