Download Multiples and Factors

Multiples and Factors
Multiples
• A multiple is formed by multiplying a given
number by the counting numbers.
• The counting numbers are 1, 2, 3, 4, 5, 6,
etc.
Example: List the multiples of 4:
•
•
•
•
•
•
4x1=4
4x2=8
4 x 3 = 12
4 x 4 = 16
4 x 5 = 20
4 x 6 = 24
Counting Numbers
So, the multiples of 4
are 4, 8, 12, 16, 20, 24,
28, etc.
What are the first five multiples of 13?
13 x 1 =13
13 x 2 = 26
13 x 3 = 39
13 x 4 = 52
13 x 5 = 65
13, 26, 39, 52, 65
Find the Missing Multiples
30
24 ____
• 6, 12, 18, ____,
15____,
1821
3 6, 9, 12, ____,
• ___,
72
• ___,
12 24, 36, 48, 60, ____
Factors
• Factors are the numbers you multiply together
to get a product.
• For example, the product 24 has several
factors.
• 24 = 1 x 24
• 24 = 2 x 12
• 24 = 3 x 8
• 24 = 4 x 6
• SO, the factors are 1, 2, 3, 4, 6, 8, 12, 24
Finding Factors
• Start with 1 x the number.
• Try 2, 3, 4, etc.
• When you repeat your factors, cross out
the repeat - you’re done at this point.
• If you get doubles (such as 4 x 4), then
you’re done. Repeats or doubles let you
know you’re done.
What are the factors of 16?
1 x 16
2x8
3 x ??
4x4
3 is not a factor, so cross it out
doubles = done
The factors of 16 are
1,2,4,8,16
What are the factors of 18?
1
2
3
4
5
6
x
x
x
x
x
x
18
9
6
??
??
3
The factors are
1,2,3,6,9,18
Repeat! Cross it out!
We’re done!
What are the factors of 7?
1x7
2 x ??
3 x ??
4
5
6
7
x
x
x
x
??
??
??
1
The only factors
of 7 are 1,7
This works, but it is a repeat. We
are done.
Prime and Composite Numbers
Prime numbers are
numbers that only have
two factors: one, and the
number itself.
EXAMPLES:
3, 5, 7, 11, 31
Composite numbers
have more than two
factors.
EXAMPLES:
6, 18, 30, 100