Factor Trees Probability, Ratios And Rates Worksheet Page 2
ADVERTISEMENT
1
2
3
4
5
6Mathematical Practices
SMP1, SMP2, SMP3, SMP5, SMP6, SMP7, SMP8
Content Standards
Getting Started
5.NF.7a, 5.NF.7b, 5.NF.7c
Mental Math and Reflexes
Math Message
Have students compute each quotient and explain their answer using the
Solve Problems 1 and 2
relationship between multiplication and division.
on journal page 393.
_
_
1
1
_
_
5 ÷ (
) =
10 because 10 ∗ (
) = 5.
1
1
15 because 15 ∗ (
5 ÷ (
) =
) = 5.
2
2
3
3
_
_
_
_
1
1
1
1
_
_
_
_
) ∗ 2 =
) ÷ 2 =
1
1
1
) ∗ 3 =
1
) ÷ 3 =
(
because (
.
(
because (
.
4
8
8
4
5
15
15
5
_
_
_
_
1
1
1
) ∗ 4 =
1
) ÷ 4 =
(
because (
.
2
8
8
2
_
_
1
1
6 ÷ (
) =
24 because 24 ∗ (
) = 6.
4
4
1
Teaching the Lesson
Interactive whiteboard-ready
ePresentations
are available at
Math Message Follow-Up
WHOLE-CLASS
to
DISCUSSION
help you teach the lesson.
(Math Journal 2, p. 393; Student Reference Book Glossary)
Have students read the definitions for factor, factor pair, composite
number, prime number, and factor string in the Student Reference
Book Glossary. Read and discuss how the terms relate. Discussion
should include the following points:
A factor of a number can be any type of number, but the other
terms only refer to whole numbers.
Numbers can be defined by their factors. For example, a prime
number has only two whole-number factors, 1 and itself.
A composite number has more than two whole-number factors.
A square number has an odd number of factors.
Each factor in the longest factor string of a number is prime.
The longest factor string is called its prime factorization.
Student Page
Date
Time
Ask: What device can be used to find all the factor pairs for a number?
LESSON
Factors
12 1
Factor rainbow
Have students make factor rainbows for 48 and
share their solutions using the Class Data Pad. A factor tree is a
Math Message
Write all the pairs of factors whose product is 48. One pair has been done for you.
1.
device that can be used to find the prime factorization of a number.
1 48; 2 24; 3 16; 4 12
6
8,
48
Draw one for 48 on the Class Data Pad. Ask: What is the prime
2.
One way to write 36 as a product of factors is 2
18. Another way is 2
2
9. Write 36
as the product of the longest possible string of factors. Do not include 1 as a factor.
2 ∗ 2 ∗ 2 ∗ 2 ∗ 3
factorization for 48?
Have students refer to the
2
2
3
3
factor tree examples for 45 on Math Journal 2, page 393. Note that
Factor Trees and Greatest Common Factors
One way to find all the prime factors of a number is to make a factor tree. First write
each factor tree begins with two different factors for 45 but the
the number. Underneath the number write any two factors whose product is that number.
Then write factors of each of these factors. Continue until all the factors are prime
prime factorizations are the same. Ask students to make factor
numbers. Below are two factor trees for 45.
45
45
trees for 36. Ask: What do you notice about the longest factor string
3
15
9
5
3
3
5
3
3
5
you recorded for Problem 2 and the result of your factor tree for 36?
The greatest common factor of two whole numbers is the largest number that is a
They are the same: 2 ∗ 2 ∗ 3 ∗ 3.
factor of both numbers.
Example:
Find the greatest common factor of 24 and 60.
Step 1
List all the factors of 24: 1, 2, 3, 4, 6, 8, 12, and 24.
Step 2
List all the factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60.
1, 2, 3, 4, 6, and 12 are on both lists. They are common factors. 12 is the
Step 3
WHOLE-CLASS
Finding Greatest
largest number, so it is the greatest common factor of 24 and 60.
ACTIVITY
Find the greatest common factor of 18 and 27.
3.
Common Factors
1, 2, 3, 6, 9, 18
Factors of 18:
1, 3, 9, 27
SOLVING
Factors of 27:
(Math Journal 2, pp. 393–395)
9
Greatest common factor:
Write the numbers 18 and 30 on the board. Ask students to name
Math Journal 2, p. 393
all the factors of each number while you list them.
Lesson 12 1
915
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education