Day 6 Class 5 Prime and Composite Numbers

Multiple Choice

Which of these numbers is prime?

• 9

• 11

• 15

• 21

Open Ended

Write one prime number and one composite number with explanation.

Multiple Choice

Which is the prime factorisation of 36?

• 2 × 2 × 3 × 3

• 6 × 6

• 12 × 3

• 9 × 4

Reorder

Arrange the steps of division method for 60:

• Divide by 2 → 30 

• Divide by 2 → 15 

• Divide by 3 → 5 

• Divide by 5 → 1

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Choice

Ravi says “60 = 2 × 2 × 15 is prime factorisation.” Is he correct?

• Yes

• No, because 15 is not prime

• No, because 2 is not prime

• Yes, because 60 = 60

Open Ended

Which method did your group prefer for factorisation today: factor tree or division? Why?

Multiple Choice

Circle all the prime numbers: 15, 17, 21, 23, 29, 33, 37, 39

• 17, 23, 29, 37

• 15, 21, 33

• 23, 33, 39

• 17, 23, 29 only

Multiple Choice

Find the prime factorisation of 48.

• 2 × 24

• 2 × 2 × 2 × 2 × 3

• 4 × 12

• 6 × 8

Open Ended

Is 1 a prime number? Explain why or why not.

Match

Match each concept with its description:

• Prime Numbers

• Composite Numbers

• Prime Factorisation

Numbers with exactly 2 factors

Numbers with more than 2 factors

Writing a number as product of primes

• Numbers with exactly 2 factors

• Numbers with more than 2 factors

• Writing a number as product of primes