1. Write all the factors of 10. Why is 10 not a prime number?
2. Write all the factors of 3 . Why is 3 a prime number ?
3. How many factors has the number 14 ? Is 14 a prime number or not?
4. Explain why the number 1 is not a prime number.
5. For each of the following numbers :-
- list all of its factors, and state whether or not it is a prime number.
a 5
b 16
C 15
e 23
f 27
\( 9 \quad 29 \)
i 44
j 47
k 51
11
6. A number which is not a prime, is called a composite number.
62
State which of the following numbers are composite :-
\[
20,37,42,33,36,37,40,41,43,49,50
\]
7. Is 2 a prime number? Give a reason for your answer.
8. a How long would it take you to write down all of the odd prime numbers?
b How long would it take you to write down all of the even prime numbers? Try it.
CfE Book 3 b - Chapter 3
this is page 30
Multiples and Fac