Primes and rules

1. Which number is prime?

• 21
• 23
• 25
• 27

2. How many factors does a prime number have?

Answer:

3. Which number is composite?

• 11
• 13
• 15
• 17

4. 2 is the only even prime number.

• True
• False

5. A rule says multiply by 4. If the input is 9, what is the output?

Answer:

6. A rule says add 3 then double. If the input is 5, what is the output?

• 13
• 16
• 18
• 26

7. What comes next? 2, 6, 12, 20, __

Answer:

8. A rule turns 3 into 10 and 5 into 16. What is the rule?

• Multiply by 3 then add 1
• Add 7
• Multiply by 2 then add 4
• Double it

9. 9 is a prime number.

• True
• False

10. Which of these is both a multiple of 3 and a factor of 18?

• 6
• 4
• 8
• 15