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Prime and Composite Numbers

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Prime and Composite Numbers worksheet preview

Prime and Composite Numbers

Prime and composite numbers illustration

📚 Part 1: Identifying Prime and Composite Numbers

1. Circle whether each number is prime or composite:

7:

Prime
Composite

12:

Prime
Composite

17:

Prime
Composite

25:

Prime
Composite

2. True or False? Circle your answer:

a) The number 1 is a prime number.

True
False

b) All even numbers except 2 are composite.

True
False

c) A prime number has exactly two factors.

True
False

3. List all the factors of these composite numbers:

Factors of 18: ________________________________

Factors of 24: ________________________________

Factors of 30: ________________________________

🌳 Part 2: Factor Trees

4. Complete these factor trees by filling in the missing numbers:

Factor tree for 20:

20 = _____ × _____

Prime factorisation: 20 = _____ × _____ × _____

Factor tree for 36:

36 = _____ × _____

Prime factorisation: 36 = _____ × _____ × _____ × _____

5. Draw your own factor tree for 28:

🚀 Part 3: Challenge Questions

6. Which of these numbers greater than 50 are prime? Circle all that apply:

51

53

57

59

61

7. Explain in your own words the difference between prime and composite numbers:
8. Find the smallest composite number that has exactly 6 factors:

Answer: _________

List the 6 factors: _________________________________

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