FACTORS & MULTIPLES

Mrs. Walker

4th grade math

FACTORFactors are

numbers that are multiplied

8 X 8 = 64

…find all the numbers you can multiply

together to get that number as the product.

What does

“Find the factors”

mean?

EVERY number greater than 1

has the number 1 and itself as a

factor.

WHAT ARE THE FACTORS OF 27?

27:1 X 273 X 9

HINT:Always write factors from least to greatest.

Remember, you are being asked to find all the numbers that can be multiplied together to get the answer 27.

1, 3, 9, 27

PRACTICEFind the factors:1. 182. 243. 214. 52

COMMON FACTORS

What does COMMON mean?What does FACTORS mean?

So….. COMMON FACTORS are:Factors that two or more

numbers have in common

WHAT ARE THE COMMON FACTORS OF 16 AND 24?

161 X 16

2 X 84 X 4

241 X 24 2 X 12 3 X 8 4 X 6 Hint: Once you repeat a

number you’re done!!

16: 1, 2, 4, 8, 16 24: 1, 2, 3, 4, 6, 8, 12, 24

Common Factors: 1, 2, 4, 8

PRACTICEWhat are the common factors of:1. 6 & 92. 24 & 483. 25 & 45

GREATEST COMMON FACTOR

The greatest factor that both numbers have in

common.

GCF = Greatest Common Factor

FIND THE GCF9

1 x 9 3 x 3

9 : 1,3,9

121 x 12 2 x 6 3 x 4

12: 1,2,3,4,6,12

PRACTICE

Find the GCF:1. 12 & 262. 9 & 21

WHITE BOARD PRACTICE

List the factors:1. 362. 183. 27List the common factors:4. 18, 225. 52, 366. 14, 9List the GCF:7. 25, 408. 30, 42

INDEPENDENT PRACTICE

Math BookPg. 112 #s 11-18

AndPg. 113 #s 36-43

MULTIPLESA multiple is the

product of a given whole number and

another whole number.4

,8,

12,

16,

20,24…

4:

MULTIPLEMultiples form a

skip counting pattern!

5: 5, 10, 15, 20, 25, 30…

LIST THE MULTIPLES OF 7 UP TO 42

7:7,

14,

21,

28,

35,42…

You use the INVERSE OPERATION

of multiplication to see if a specific number is a multiple of the given

number.

Example:Is 108 a multiple of 6?

PRACTICE1. Find the first 10 multiples of 32. Find the first 6 multiples of 83. Is 40 a multiple of 8? Why?4. Is 63 a multiple of 5? Why?

COMMON MULTIPLEA multiple that 2 or more

numbers have in common. Example: Find the first 3 common multiples of 3 and 6.

CM: 6, 12, 18

3,

6,

9,12,

15,18…

3: 6

,12,

18,

24,

30,36…

6:

IS 36 A COMMON MULTIPLE OF 6 AND 9?

What strategy would you use?That’s Right! Division

36 ÷ 6= ?36 ÷ 9=?

Yes! 36 is a common multiple of 6 and 9.

PRACTICE1. Is 42 a common multiple of 6 and 9?

List 10 multiples of each number and circle the common multiples.

2. 3 and 63. 4 and 124. 2 and 5

LEAST COMMON MULTIPLE

The smallest multiple that 2 or more numbers have in common.

LCM = Least Common Multiple

Example: Find least common multiples of 6 and 8.

LCM: 24

6,

12,

18,

24,

30,36…

6: 8

,16,

24,32,

40,48…

8:

WHITE BOARD PRACTICEList the first 5 multiples of each number.1. 22. 43. 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.

INDEPENDENT PRACTICE

MB pg. 112 #s 19-26And

MB pg. 113 #s 44-52