Primes to 100

Which of the following is a common multiple of 4 and 6?

• 8

• 12

• 16

• 20

What makes a number a prime number?

• It is divisible by 3.

• It is an even number.

• It has exactly two factors: 1 and itself.

• It has only one factor.

Which of these is the only even prime number?

• 8

• 2

• 6

• 4

What are the prime factors of 24?

• 2, 3, and 6

• 2, 3, and 4

• 2, 2, 2, and 3

• 3, 4, and 6

Which pair of prime numbers adds up to 30?

• 11 and 21

• 19 and 9

• 7 and 23

• 13 and 15