Download Find the Factors of a Number

NS 4.1
Understand that many whole numbers break down in different
ways (e.g., 12 4 3 2 6 2 2 x 3).
UNDERLYING SKILLS AND CONCEPTS:
multiplication basic facts;
meaning of multiplication
Find the Factors of a Number
E x am p l E
E x am p l E
a
Every whole number greater than 1
has at least two factors, 1 and itself.
Many whole numbers have more
than two factors.
1
Find all the factors of 15.
Remember the multiplication
basic facts:
2
Find all the factors of 18.
You can find factors on a multiplication
table.
Find all the 18s.
Note the factors for each.
1 15 15
3 5 15
So, the factors of 15 are:
1, 3, 5, and 15
Factor Factor Product
ltip
Mu
0
1
2
3
4
5
6
7
8
9 10
0 0
0
0
0
0
0
0
0
0
0
1 0
1
2
3
4
5
6
7
8
9 10
2 0
2
4
6
8 10 12 14 16 18 20
3 0
3
6
9 12 15 18 21 24 27 30
4 0
4
8 12 16 20 24 28 32 36 40
5 0
5 10 15 20 25 30 35 40 45 50
6 0
6 12 18 24 30 36 42 48 54 60
7 0
7 14 21 28 35 42 49 56 63 70
8 0
8 16 24 32 40 48 56 64 72 80
9 0
9 18 27 36 45 54 63 72 81 90
0
ly
10 0 10 20 30 40 50 60 70 80 90 100
Multiply
Mrs. Multiply
page 98
1 12 12 and 2 6 12. So 1, 2,
3, 4, 6, and 12 are all factors of 12.
1 18, 2 9, 3 6
Factors of 18 are: 1, 2, 3, 6, 9, and 18.
Chapter 9 – Lesson 1
D – © CSL Associates, Inc. All rights reserved.
K
The numbers that are
multiplied together to
ey Ide
obtain a product are factors.
3 4 12
So, 3 and 4 are two factors of 12.
Name
P RAC T I C E
D – © CSL Associates, Inc. All rights reserved.
List all of the ways to factor each number.
1. 2
12
2. 3
13
3. 4
1 4; 2 2
4. 5
15
5. 6
1 6; 2 3
6. 8
1 8; 2 4
7. 10
1 10; 2 5
8. 14
1 14; 2 7
9. 16
1 16; 2 8; 4 4
10. 20
1 20; 2 10; 4 5
11. 22
1 22; 2 11
12. 24
1 24; 2 12; 3 8; 4 6
Answer Yes or No to the questions. Explain how you decided.
13. Does every number always have 1 as one of its factor?
Yes
14. Does a number always have itself as a factor?
Yes
15. Are there any numbers that do not have any factors?
No
16. Can a number have only one factor (hint: try number 1)?
Yes
17. Are there any numbers that have only 2 factors?
Yes
18. Are there any numbers that have more than 5 factors?
Yes
Math
Reasoning
Mystery Number
19. I am the largest number that is a factor of both 12 and 18.
Who am I?
Chapter 9 – Lesson 1
MR 1.1
6
page 99
MCX94.HW.CL.G4.FM&Lesson.v211
8/2/04
19:16
Page 66
Name
P RAC T I C E
…at home!
1. 4
1 4; 2 2
2. 6
1 6; 2 3
3. 7
17
4. 8
1 8; 2 4
5. 9
1 9; 3 3
6. 10
1 10; 2 5
7. 12
1 12; 2 6; 3 4
8. 16
1 16; 2 8; 4 4
9. 20
1 20; 2 10; 4 5
10. 21
1 21; 3 7
11. 24
1 24; 2 12; 3 8; 4 6
12. 28
1 28; 2 14; 4 7
D – © CSL Associates, Inc. All rights reserved.
List all of the ways to factor each number.
Answer Yes or No to the questions. Explain how you decided.
13. Are there any numbers that have only 2 factors?
14. Can a number have only one factor (hint: try number 1)?
15. Are there any numbers that have more than 5 factors?
Yes
Yes; 1
Yes; 24
16. Does a number always have itself as a factor?
Yes
17. Does every number always have 1 as one of its factor?
Yes
18. Are there any numbers that do not have any factors?
No
Math
Reasoning
Mystery Number
19. I am the largest number that is a factor of both 18 and 27.
Who am I?
page 66
Home Resource and Homework
MR 1.1
9
Chapter 9 Lesson 1