Prime Numbers & Factors Quiz

1. What is a prime number?

1. A number divisible by itself only
2. A number greater than 10
3. A number with exactly two factors: 1 and itself
4. An odd number

2. Which of these is NOT a prime number?

1. 11
2. 13
3. 15
4. 17

3. What is the only even prime number?

1. 1
2. 2
3. 4
4. 6

4. What are the prime factors of 12?

1. 1, 2, 3 and 4
2. 2 and 3
3. 2, 3 and 4
4. 3 and 4

5. What is the HCF (Highest Common Factor) of 24 and 36?

1. 12
2. 4
3. 6
4. 8

6. What is the LCM (Lowest Common Multiple) of 4 and 6?

1. 12
2. 18
3. 2
4. 24

7. Express 30 as a product of prime factors.

1. 2 × 15
2. 2 × 3 × 5
3. 3 × 10
4. 5 × 6

8. How many prime numbers are there between 1 and 20?

1. 6
2. 7
3. 8
4. 9

9. What is the LCM of 3, 4 and 6?

1. 12
2. 18
3. 24
4. 6

10. Is 97 a prime number?

1. No, it's divisible by 11
2. No, it's divisible by 3
3. No, it's divisible by 7
4. Yes

11. What is the HCF of 15 and 25?

1. 10
2. 15
3. 3
4. 5

12. Write 72 as a product of its prime factors in index form.

1. 2³ × 3²
2. 2⁴ × 3
3. 4 × 18
4. 8 × 9

13. What is a composite number?

1. A number divisible by 10
2. A number made by adding two primes
3. A number with more than two factors
4. A very large number

14. Find the LCM of 8 and 12.

1. 16
2. 24
3. 4
4. 96

15. What are twin primes?

1. Pairs of primes that differ by 2
2. Primes that are both even
3. Primes that double each other
4. Two consecutive prime numbers

16. What is the HCF of 42 and 70?

1. 10
2. 14
3. 21
4. 7

17. Is 1 a prime number?

1. No, it has only one factor
2. No, it is a composite number
3. Yes, it is the smallest prime
4. Yes, it only divides by 1

18. What is the prime factorisation of 100?

1. 10²
2. 2 × 50
3. 2² × 5²
4. 4 × 25

19. What is the smallest prime number greater than 50?

1. 51
2. 52
3. 53
4. 57

20. Use the HCF of 18 and 30 to simplify the fraction 18/30.

1. 2/3
2. 3/5
3. 6/10
4. 9/15