The Ladder Method
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Transcript of The Ladder Method
![Page 1: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/1.jpg)
The Ladder Method
For Finding LCD, GCF and
Simplifying Fractions
Becky Afghani, LBUSD Math Curriculum Office, 2003
![Page 2: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/2.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
The Ladder Method...is a method of factoring which allows
you to factor two numbers at once in order to…
• find the LCM of the two numbers• find the GCF of the two numbers
![Page 3: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/3.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Use the ladder to factor6 and 8
You will divide out any common factors of the two numbers
What number goesinto both 6 and 8?
Now divide both6 and 8 by the 2
Does any # besides 1go into both 3 and 4?No? Then you are done.
![Page 4: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/4.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Let’s find the Least Common Multiple (LCM) of
6 and 8The LCM is the product of all the
numbers on the left and the bottom.
The LCMof
6 and 8is 24.
![Page 5: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/5.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Which numbers in the ladder give you the LCM?
The “L” shape gives you the LCM: multiply the numbers
on the left and bottom.
![Page 6: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/6.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
What about the Greatest Common Factor (GCF) of 6 and
8?The GCF is the product of all the
numbers on the left.
The GCFof
6 and 8is 2.
![Page 7: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/7.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Which numbers in the ladder give you the GCF?
Multiply the numbers on the left only for the GCF.
![Page 8: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/8.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Let’s try some bigger numbers.
Divide out all the common factors down the left side.
What numbergoes into both
24 and 60?Does any #
besides 1go into both 12 and 30?How about6 and 15?
Anything else?No?
You’re done.
![Page 9: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/9.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
x
x
xx
Find the LCM.
=120
The LCMof
24 and 60is 120.
![Page 10: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/10.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
x
x
Find the GCF.
=12
The GCFof
24 and 60is 12.
![Page 11: The Ladder Method](https://reader035.fdocuments.net/reader035/viewer/2022071711/56812bcb550346895d90224e/html5/thumbnails/11.jpg)
Becky Afghani, LBUSD Math Curriculum Office, 2003
Practice. Find the LCM and Practice. Find the LCM and
GCF for 28 and 42. GCF for 28 and 42.
LCM = 2 7 2 3 = 84
GCF = 2 7 = 14