1. Can you find the missing numbers ? What’s the connection ?
Factors
Can you find the missing numbers ?
What’s the connection ? 1 3 12 6 4

2. Factors The numbers in the outer circles are factors
of the numbers in the centre of the circle.
Example
The factors of 12 are 12,6,4,3,2,and 1.

3. Squares and Primes
Some of your factor diagrams have only two factors, these numbers are called prime numbers.
Another group of diagrams have an ODD number of factors around the centre number. These are the square numbers.

4. Squares and Primes
Make a list of the numbers 1 to 30 and their factors. Make a note if they are prime of square numbers.
Example
Number
Factors
Type 1
Square 2
1,2
Prime 3
1,3

5. Multiples 3,6,9,12,15 …. etc. Are multiples of 3.
How would you explain what a multiple is?

6. Common Multiples
3,6,9,12,15,18,21,24,27,30,33,36
4,8,12,16,20,24,28,32,36,40,44,48
Examine the lists above.
Which numbers are multiples of 3 and 4 ?
We call these numbers common multiples.
Which is the lowest common multiple ?
Can you predict what the next common
multiple will be ?
Explain how you did it.

7. Primes and Prime Factors
Some Facts
Numbers which have exactly two factors
are called PRIME NUMBERS.
2 is the first prime number and the only even
prime number.

8. Card Puzzle You will need at set of 1 to 50 number cards.
Work with a friend and sort the numbers into two groups, PRIMES and NON PRIMES.

9. Here is a prime factor tree for 36.