Prime Numbers and Prime Factorisation

What is a prime number?

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

• A prime number is a whole number that can be divided evenly by numbers other than 1 and itself.

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

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

Identify the prime numbers between 1 and 20.

• 3, 6, 9, 12, 15, 18

• 2, 3, 5, 7, 11, 13, 17, 19

• 2, 4, 6, 8, 10, 12, 14, 16, 18, 20

• 1, 4, 6, 8, 10, 12, 14, 16, 18, 20

Find the prime factors of 24.

• 4, 6

• 3, 3, 3

• 2, 2, 6

• 2, 2, 2, 3

What is the prime factorisation of 36?

• 2^2 * 3^2

• 2^2 * 3^3

• 2^3 * 3

• 2^4 * 3

Apply prime factorisation to find the LCM of 12 and 15.

• 28

• 45

• 20

• 60

Identify the non-prime numbers between 30 and 40.

• 30, 31, 33, 37, 39, 40

• 30, 32, 34, 35, 36, 38, 39, 40

• 29, 31, 33, 37, 39, 41

• 31, 33, 37, 39, 40

What is the smallest prime number?

• 1

• 3

• 5

• 2

Find the prime factors of 56.

• 2, 2, 2, 2, 7

• 2, 2, 2, 7

• 3, 3, 5

• 1, 1, 1, 1, 1, 1, 1, 7

What is the prime factorisation of 90?

• 3 x 3 x 10

• 2 x 5 x 9

• 2 x 3 x 3 x 5

• 2 x 2 x 3 x 15

Apply prime factorisation to find the HCF of 18 and 24.

• 8

• 6

• 3

• 12