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Factors, Primes &
Composite Numbers
O Product – An answer to a
multiplication problem.
7 x 8 = 56
Product
O Factor – a number that is
multiplied by another to give a
product.
7 x 8 = 56
Factors
O Factor – a number that
divides evenly into another.
56 ÷ 8 = 7
Factor
ARRANGEMENT OF COUNTERS
Take 6 counters and arrange
them in different
ways
5
1 Row × 6 Counters = 6 Counters
6
3 Rows × 2 Counters per row = 6 Counters
7
2 Rows × 3 counters per row = 6 counters
8
6 Rows × 1 counter = 6
counters
9
As we can see, 6 can be written as
product of two numbers in many
ways:
1×6=6
2×3=6
3×2=6
6×1=6
1, 2, 3 and 6 are factors of 6
10
What are the factors?
6 x 7 = 42
7 x 9 = 63
8 x 6 = 48
4 x 9 = 36
6&7
7&9
8&6
4&9
What are the factors?
42 ÷ 7 = 6
63 ÷ 9 = 7
48 ÷ 6 = 8
36 ÷ 9 = 4
7
9
6
9
Who has heard of a
Factor Rainbow?
A factor rainbow helps you find all of the factors
of a number. It is called a rainbow because all
of the factor pairs connect to make a rainbow!
How do we do it!?!?!?
Making a factor rainbow is easy as pie!
Let’s try one:
Find all of the factors for the number 12.
We start by counting and seeing if a
number can be multiplied to equal 12.
1
2
3
4
6
How many factor
pairs are there for the
number 12?
3
12
One more time...
How many factor pairs are there for the number 18?
3
1
2
3
6
9
18
YOU TRY!
Make factor rainbows for the
following numbers and tell how
many factor pairs each number
has.
15
24
 Prime Number – a number
that has only two factors, itself
and 1.
7
7 is prime because the only numbers
that will divide into it evenly are 1 and 7.
Examples of Prime
Numbers
2, 3, 5, 7, 11, 13, 17
Special Note:
One is not a prime number.
 Composite number – a
number that has more than two
factors.
8
The factors of 8 are 1, 2, 4, 8
Examples of Composite
Numbers
4, 6, 8, 9, 10, 12
Our Lonely 1
It is not prime
because it does
not have exactly
two different
factors.
It is not
composite
because it does
not have more
than 2 factors.
Special Note:
One is not a prime nor
a composite number.