1. Mrs. Walker 4th grade math
Factors & Multiples
Mrs. Walker
4th grade math

2. Factors are numbers that are multiplied 8 X 8 = 64

3. What does
“Find the
factors”
mean?
…find all the numbers you can multiply together to get that number as the product.

4. EVERY number greater than 1 has the number 1 and itself as a factor.

5. Always write factors from least to greatest.
What are the factors of 27?
Remember, you are being asked to find all the numbers that can be multiplied together to get the answer 27.
27:
1 X 27
3 X 9
HINT:
Always write factors from least to greatest.
1, 3, 9, 27

6. practice
Find the factors: 18 24 21 52

7. Factors that two or more numbers have in common
Common Factors
What does COMMON mean?
What does FACTORS mean?
So…..
COMMON FACTORS are:
Factors that two or more numbers have in common

8. What are the common factors of 16 and 24?
1 X 16
2 X 8
4 X 4
24 1 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

9. Practice
What are the common factors of:
6 & 9
24 & 48
25 & 45

10. Greatest Common Factor
The greatest factor that both numbers have in common.
GCF = Greatest Common Factor

11. Find the GCF
9 1 x 9 3 x 3 9 : 1,3,9
12 1 x 12 2 x 6 3 x 4 12: 1,2,3,4,6,12

12. Practice
Find the GCF:
12 & 26
9 & 21

13. White board Practice List the factors: 36 18 27
List the common factors:
18, 22
52, 36
14, 9
List the GCF:
25, 40
30, 42

14. Math Book Pg. 112 #s 11-18 And Pg. 113 #s 36-43
Independent Practice
Math Book Pg. 112 #s And Pg. 113 #s 36-43

15. Multiples
A multiple is the product of a given whole number and another whole number. 4: 4, 8,
12,
16,
20,
24…

16. Multiples form a skip counting pattern!
5: 5, 10, 15, 20, 25, 30…

17. List the multiples of 7 up to 427: 7,
14,
21,
28,
35,
42…

18. Example: Is 108 a multiple of 6? 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?

19. Practice Find the first 10 multiples of 3
Is 40 a multiple of 8? Why?
Is 63 a multiple of 5? Why?

20. A multiple that 2 or more numbers have in common.
Common Multiple
A 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: 3, 6, 9,
12,
15,
18… 6: 6,
12,
18,
24,
30,
36…

21. 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.

22. Practice
1. Is 42 a common multiple of 6 and 9?
List 10 multiples of each number and circle the common multiples.
2. 3 and 6
3. 4 and 12
4. 2 and 5

23. 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: 6,
12,
18,
24,
30,
36… 8: 8,
16,
24,
32,
40,
48…

24. White board Practice List the first 5 multiples of each number. 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.

25. Independent Practice
MB pg. 112 #s And MB pg. 113 #s 44-52