Math Quiz: Take A Short Test On Prime Numbers

1) What is the only even prime number?

1

2

4

6

The only even prime number is 2. All other even numbers greater than 2 are divisible by 2, making them composite numbers.

Explanation

The only even prime number is 2. All other even numbers greater than 2 are divisible by 2, making them composite numbers.

2) Is 23 a prime number?

Yes

No

23 is prime. It has no factors other than itself and 1.

Explanation

23 is prime. It has no factors other than itself and 1.

3) Which of the following numbers is NOT a prime number?

11

15

23

31

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 15 is not a prime number because it is divisible by 1, 3, 5, and 15.

Explanation

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 15 is not a prime number because it is divisible by 1, 3, 5, and 15.

4) Is 35 a prime number?

Yes

No

35 is not a prime number since 35 = 5*7. 35 is divisible by 5 and 7.

Explanation

35 is not a prime number since 35 = 5*7. 35 is divisible by 5 and 7.

5) Which of the following statements about prime numbers is true?

Every prime number is odd.

Every prime number is even.

1 is a prime number.

Prime numbers are only divisible by 1 and themselves.

This statement correctly defines prime numbers. A prime number is a natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself. This property distinguishes prime numbers from composite numbers.

Explanation

This statement correctly defines prime numbers. A prime number is a natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself. This property distinguishes prime numbers from composite numbers.

6) Select all the numbers that are prime numbers.

7

21

13

10

7 and 13 are prime.
21 = 7*3 and 10 = 2*5 are not prime.

Explanation

7 and 13 are prime.
21 = 7*3 and 10 = 2*5 are not prime.

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7) Which of the following is a prime number?

27

29

30

33

29 is a prime number because it has only two positive divisors: 1 and 29. It is not divisible by any other number.

Explanation

29 is a prime number because it has only two positive divisors: 1 and 29. It is not divisible by any other number.

8) What is the smallest prime number?

0

1

2

3

The smallest prime number is 2. It is the only even prime number and the only prime number that is even. All other prime numbers are odd.

Explanation

The smallest prime number is 2. It is the only even prime number and the only prime number that is even. All other prime numbers are odd.

9) How many prime numbers are there between 1 and 20?

6

7

8

9

To find the number of prime numbers between 1 and 20, we list the prime numbers in that range. Prime numbers are numbers greater than 1 that have no divisors other than 1 and themselves. Here are the prime numbers between 1 and 20:

2, 3, 5, 7, 11, 13, 17, 19

Counting these numbers, there are 8 prime numbers between 1 and 20. Therefore, the correct answer is:

8

Explanation

To find the number of prime numbers between 1 and 20, we list the prime numbers in that range. Prime numbers are numbers greater than 1 that have no divisors other than 1 and themselves. Here are the prime numbers between 1 and 20:

2, 3, 5, 7, 11, 13, 17, 19

Counting these numbers, there are 8 prime numbers between 1 and 20. Therefore, the correct answer is:

8

10) A _____ number is a natural number that's not a prime number.

A composite number is a natural number that is not a prime number. This means that it can be divided evenly by more than just 1 and itself. In other words, it has multiple factors. For example, 4 is a composite number because it can be divided evenly by 1, 2, and 4. On the other hand, prime numbers can only be divided evenly by 1 and themselves. Therefore, composite numbers are the opposite of prime numbers.

Explanation

A composite number is a natural number that is not a prime number. This means that it can be divided evenly by more than just 1 and itself. In other words, it has multiple factors. For example, 4 is a composite number because it can be divided evenly by 1, 2, and 4. On the other hand, prime numbers can only be divided evenly by 1 and themselves. Therefore, composite numbers are the opposite of prime numbers.

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