Unit 2
 A multiple is formed by multiplying a given
number by the counting numbers.
 The counting numbers are 1, 2, 3, 4, 5, 6, etc.
 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.
13 x 1 =?
13 x 2 = ?
13 x 3 = ?
13 x 4 = ?
13 x 5 = ?
13, 26, 39, 52, 65
30
24 ____
 6, 12, 18, ____,
3 6, 9, 12, ____,
15 ____,
18 21
 ___,
72
12 24, 36, 48, 60, ____
 ___,
Product – An answer to a
multiplication problem.
7 x 8 = 56
Product
Factor – a number that is
multiplied by another to give a
product.
7 x 8 = 56
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
 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.
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
 How do we find the factors for a given number?
 Using a multiplication square…
 Factor ninja
 Multiple Monster
 Chops numbers up!
 Makes Number Big
 Exp: 24
 Exp: 12
 1 x 24
 12
 2 x 12
 24
 3x8
 36
 4x6
 48
 60
Factors: 1,2,3,4,6,8,12,24
 72
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!
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.
 72
 85
 60
 15
 7
 81
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