Prime Numbers Challenge

What is a prime number?

• A prime number is a number that is divisible by 4.

• A prime number is a number that is divisible by 3.

• A prime number is a number that is divisible by 2.

• A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Is 1 a prime number? Why or why not?

• No

• Maybe

• Sometimes

• Yes

Identify the prime numbers between 1 and 20.

• 4

• 6

• [2, 3, 5, 7, 11, 13, 17, 19]

• 8

What are the prime factors of 24?

• 2, 2, 2, 3

• 2, 4, 6, 8

• 2, 2, 3, 3

• 3, 3, 3, 3

Determine if 37 is a prime number.

• Yes, 37 is a composite number.

• Yes, 37 is a prime number.

• No, 37 is not a prime number.

• No, 37 is divisible by 3.

Calculate the prime factorization of 56.

• 2^3 * 8

• 2^4 * 7

• 2^2 * 14

• 2^3 * 7

Explain how to test if a number is prime.

• Use the number itself as a divisor.

• Check divisibility of the number by odd numbers only.

• Check divisibility of the number by numbers from 2 to square root of the number.

• Check divisibility of the number by numbers from 2 to the number itself.

List the prime numbers between 20 and 40.

• 21

• 27

• 35

• [23, 29, 31, 37]

Find the prime factors of 45.

• 3, 5

• 1, 45

• 2, 3

• 5, 9

Is 50 a prime number? Why or why not?

• Yes

• Sometimes

• No

• Only on Tuesdays