&&66
)LQGDOOIDFWRUSDLUVIRUDZKROHQXPEHULQWKHUDQJH±
NS 1.4*2$
Determine
the prime factors of all numbers through 50 and write
5HFRJQL]HWKDWDZKROHQXPEHULVDPXOWLSOHRIHDFKRILWVIDFWRUV'HWHUPLQHZKHWKHUD
numbers as the product of their prime factors using exponents
JLYHQZKROHQXPEHULQWKHUDQJH±LVDPXOWLSOHRIDJLYHQRQHGLJLWQXPEHU
to show multiples of a factor (e.g., 24 ! 2 " 2 " 2 " 3 ! 8 x 3).
'HWHUPLQHZKHWKHUDJLYHQZKROHQXPEHULQWKHUDQJH±LVSULPHRUFRPSRVLWH
UNDERLYING SKILLS AND CONCEPTS:
understand factors;
use basic multiplication facts
Identify Prime and Composite Numbers
Am I prime or
composite?
A prime number is a number greater than one
that has only two factors: itself and 1.
To decide if a number is prime, check if you can
divide it evenly by a number other than 1 or itself.
15
If you can, the number is composite.
Hey, remember:
I can divide any
number evenly,
so I don't count
when looking for
prime numbers.
Mr.
5
Ms.
Factor
Div
.rM
Factor
1
1 Area = 6 square units
You can arrange 6 tiles in 1 row of 6,
2 rows of 3, or 3 rows of 2.
2
So, the factors of 6 are: 1, 2, 3, and 6.
Area = 6
square
units
Area
=6
square
units
3
So, 6 is a composite number.
3
2
2
Which of these numbers is prime?
12, 11, 9
You can arrange 12 tiles in
2 rows of 6, or 3 rows of 4.
So, 12 is composite.
11 has only two factors: 1, 11.
So, 11 is prime.
9 has more than two factors: 1, 3, 9.
So, 9 is composite.
So, of 12, 11, and 9, only 11 is prime.
12
1
2
Area = 12 square units
Area = 12
square units
6
1
1
6
11
here
Are t
more
ways
?
15
Prime
Compo
Area = 11 square units
9
3
Area = 9 square units
3
Area = 9
square
units
Chapter 5 – Lesson 2
E – © CSL Associates, Inc. All rights reserved.
6
Look at the arrays to decide.
page 52
3
So can 5.
So, you are
composite.
1
Is 6 prime or composite?
E x am p l E
Hey,
3 can divide
you evenly!
Area = 6 square units
E x am p l E
1
Prime
Compo
Name
P RAC T I C E
List all the factors for each number. Then tell whether the number is prime or composite.
1. 4
1, 2, 4; composite
7. 27
1, 3, 9, 27; composite
2. 14
1, 2, 7, 14; composite
8. 17
1, 17; prime
3. 43
1, 43; prime
4. 5
1, 5; prime
10. 51
1, 3, 17, 51; composite
5. 19
1, 19; prime
11. 13
1, 13; prime
6. 24
1, 2, 3, 4, 6, 8, 12, 24;
12. 41
1, 41; prime
9. 50 1, 2, 5, 10, 25, 50; composite
composite
E – © CSL Associates, Inc. All rights reserved.
Find the next prime number
13. The next prime number after 5 is
7
14. The next prime number after 11 is
13
15. The next prime number after 41 is
43
List all the prime numbers between 1 and 100.
1
16. Use the chart.
11 12 13 14 15 16 17 18 19 20
Skip count by 2, 3, 4, 5, 6, 7, 8, 9
and 10.
Cross out the multiples as you count.
Then circle the numbers that are prime.
The prime numbers between 1 and 100 are:
see circled numbers
2
3
4
5
6
7
8
9 10
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
Math
Reasoning
Number Sense
MR 2.4
17. Can a prime number ever be even?
Yes. 2 is a prime number and it is even. It is the only even
number that is prime. All other even numbers have 2 as a
factor.
Chapter 5 – Lesson 2
page 53
MCX94.HW.CL.G5.FM&Lesson.v211
8/2/04
18:02
Page 36
Name
…at home!
P RAC T I C E
List all the factors for each number. Then tell whether the number is prime or composite.
1. 6
1, 2, 3, 6; composite
7. 32 1, 2, 4, 8, 16, 32; composite
2. 15
1, 3, 5, 15; composite
3. 29
1, 29; prime
4. 7
1, 7; prime
10. 53
1, 53; prime
5. 23
1, 23; prime
11. 17
1, 17; prime
6. 28
1, 2, 4, 7, 14, 28;
1, 19; prime
8. 19
9. 40 1, 2, 4, 5, 8, 10, 20, 40: composite
12. 48 1, 2, 3, 4, 6, 8, 12, 16, 24,
48; composite
Find the next prime number
13. The next prime number after 7 is
11
14. The next prime number after 13 is
17
15. The next prime number after 43 is
47
List all the prime numbers between 1 and 100.
1
16. Use the chart.
11 12 13 14 15 16 17 18 19 20
Skip count by 2, 3, 4, 5, 6, 7, 8, 9
and 10.
Cross out the multiples as you count.
Then circle the numbers that are prime.
The prime numbers between 1 and 100 are:
see circled numbers
2
3
4
5
6
7
8
9 10
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
Math
Reasoning
Number Sense
MR 2.4
17. Can a prime number ever be even? Explain.
Yes. 2 is a prime number and it is even. It is the only even
number that is prime. All other even numbers have 2 as a
factor.
page 36
Home Resource and Homework
Chapter 5 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
composite
MCX94TEG5CH01_32.v7.4.2 2/24/01 19:43 Page 99
Name
P RAC T I C E
List all the factors for each number. Then tell whether the number is prime or composite.
1. 4
1, 2, 4; composite
7. 27
1, 3, 9, 27; composite
2. 14
1, 2, 7, 14; composite
8. 17
1, 17; prime
3. 43
1, 43; prime
4. 5
1, 5; prime
10. 51
1, 3, 17, 51; composite
5. 19
1, 19; prime
11. 13
1, 13; prime
6. 24
1, 2, 3, 4, 6, 8, 12, 24;
12. 41
1, 41; prime
9. 50 1, 2, 5, 10, 25, 50; composite
composite
E – © CSL Associates, Inc. All rights reserved.
Find the next prime number
13. The next prime number after 5 is
7
14. The next prime number after 11 is
13
15. The next prime number after 41 is
43
List all the prime numbers between 1 and 100.
1
16. Use the chart.
11 12 13 14 15 16 17 18 19 20
Skip count by 2, 3, 4, 5, 6, 7, 8, 9
and 10.
Cross out the multiples as you count.
Then circle the numbers that are prime.
The prime numbers between 1 and 100 are:
see circled numbers
2
3
4
5
6
7
8
9 10
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
Math
Reasoning
Number Sense
MR 2.4
17. Can a prime number ever be even?
Yes. 2 is a prime number and it is even. It is the only even
number that is prime. All other even numbers have 2 as a
factor.
Chapter 5 – Lesson 2
Student Book Page
page 53
Name
…at home!
P RAC T I C E
List all the factors for each number. Then tell whether the number is prime or composite.
1. 6
1, 2, 3, 6; composite
7. 32 1, 2, 4, 8, 16, 32; composite
2. 15
1, 3, 5, 15; composite
3. 29
1, 29; prime
4. 7
1, 7; prime
10. 53
1, 53; prime
5. 23
1, 23; prime
11. 17
1, 17; prime
6. 28
1, 2, 4, 7, 14, 28;
1, 19; prime
8. 19
9. 40 1, 2, 4, 5, 8, 10, 20, 40: composite
12. 48 1, 2, 3, 4, 6, 8, 12, 16, 24,
48; composite
Find the next prime number
13. The next prime number after 7 is
11
14. The next prime number after 13 is
17
15. The next prime number after 43 is
47
List all the prime numbers between 1 and 100.
1
16. Use the chart.
11 12 13 14 15 16 17 18 19 20
Skip count by 2, 3, 4, 5, 6, 7, 8, 9
and 10.
Cross out the multiples as you count.
Then circle the numbers that are prime.
The prime numbers between 1 and 100 are:
see circled numbers
2
3
4
5
6
7
8
9 10
21 22 23 24 25 26 27 28 29 30
31 32 33 34 35 36 37 38 39 40
41 42 43 44 45 46 47 48 49 50
51 52 53 54 55 56 57 58 59 60
61 62 63 64 65 66 67 68 69 70
71 72 73 74 75 76 77 78 79 80
81 82 83 84 85 86 87 88 89 90
91 92 93 94 95 96 97 98 99 100
Math
Reasoning
Number Sense
MR 2.4
17. Can a prime number ever be even? Explain.
Yes. 2 is a prime number and it is even. It is the only even
number that is prime. All other even numbers have 2 as a
factor.
page 36
Home Resource and Homework
Chapter 5 Lesson 2
E – © CSL Associates, Inc. All rights reserved.
composite