Mrs. Walker
4th grade math
Factors are
numbers that
are multiplied
8 X 8 = 64
What does
“Find the
factors”
mean?
…find all the
numbers you can
multiply together to
get that number as
the product.
EVERY number
greater than 1 has
the number 1 and
itself as a factor.
Remember, you are being asked to find all the numbers
that can be multiplied together to get the answer 27.
27:
1 X 27
3X9
27: 1, 3, 9, 27
HINT:
Always write factors from least to greatest.
Find the factors:
1. 18
2. 24
3. 21
4. 52
What does COMMON mean?
What does FACTORS mean?
So…..
COMMON FACTORS are:
Factors that two or more
numbers have in common
16
1 X 16
2X8
4X4
Hint: Once you repeat a
number you’re done!!
16: 1, 2, 4, 8, 16
24
1 X 24
2 X 12
3X8
4X6
24: 1, 2, 3, 4, 6, 8, 12, 24
Common Factors: 1, 2, 4, 8
What are the common factors of:
1. 6 & 9
2. 24 & 48
3. 25 & 45
The greatest factor that both
numbers have in common.
GCF = Greatest Common Factor
9
1x9
3x3
12
1 x 12
2x6
3x4
9 : 1,3,9
12: 1,2,3,4,6,12
Find the GCF:
1.
2.
12 & 26
9 & 21
List the factors:
1.
36
2. 18
3. 27
List the common factors:
1.
18, 22
2. 52, 36
3. 14, 9
List the GCF:
1.
25, 40
2. 30, 42
Math Book
Pg. 112 #s 11-18
And
Pg. 113 #s 36-43
Multiples form a skip
counting pattern!
5: 5, 10, 15, 20, 25, 30…
Example:
15 is a multiple of 5
because it is made up of 3
groups of 5.
Use the inverse
operation of
multiplication,
Division
To find multiples!
7: 7, 14, 21, 28, 35, 42
Strategy: Use a division number
sentence.
108 ÷ 6=
(if the quotient is a whole number then 6 is a
multiple.)
Solution: Yes, 108 is a
multiple of 6 because 108 ÷ 6=
18
Find 10 multiples of:
1.
3
2.
8
3.
11
A multiple that 2 or more
numbers have in common.
What strategy would you use?
That’s Right! Division
36 ÷ 6= ?
36 ÷ 9=?
Yes, 36 is a common multiple
of 6 and 9.
1. Is 42 a common multiple of 6 and 9?
List 10 multiples of each number and circle the
common multiples.
2. 3,6
3. 4, 12
4. 2, 5
The lowest multiple that both numbers have in
common.
LCM
EX. What is the LCM of 12 and 24?
Strategy: List the multiples of 12 and 24.
12:12,24
24: 24
List the first 5 multiples of each number.
1. 2
2. 4
3. Name the LCM of the following numbers:
20 and 5
4. How many common multiples less than 50 do 8
and 9 have? Name them
MB pg. 112 #s 19-26
And
MB pg. 113 #s 44-52