Mastering GCF and LCM with the Ladder Method

The video tutorial explains how to use the ladder method to find the least common multiple (LCM), greatest common factor (GCF), and simplify fractions. It begins with an introduction to the ladder tool, followed by instructions on setting up the ladder by drawing an upside-down division bar and writing numbers. The process involves using prime numbers, starting with the lowest, to divide the numbers. The tutorial then demonstrates how to find the LCM and GCF by multiplying specific numbers along the ladder. Finally, it shows how to simplify fractions using the same method.

What is the primary advantage of using the ladder tool?

• It is faster than other methods.

• It uses fewer steps.

• It can be used for multiple purposes like finding LCM, GCF, and simplifying fractions.

• It requires no calculations.

What is the first step in using the ladder tool?

• Drawing a circle.

• Writing two numbers on one line.

• Finding the highest prime number.

• Multiplying the numbers.

Which prime number do you start with when using the ladder tool?

• 3

• 2

• 7

• 5

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CCSS.4.OA.C.5

What do you do if a prime number does not divide both numbers evenly?

• Use the next highest prime number.

• Stop the process.

• Multiply the numbers.

• Divide by a non-prime number.

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CCSS.5.NBT.B.6

CCSS.6.NS.B.2

How do you find the least common multiple (LCM) using the ladder tool?

• By adding the numbers in an L shape.

• By multiplying the numbers in an L shape.

• By dividing the numbers in an L shape.

• By subtracting the numbers in an L shape.

What is the least common multiple (LCM) of 24 and 36 using the ladder tool?

• 60

• 72

• 84

• 48

Where do you find the greatest common factor (GCF) on the ladder tool?

• Along the bottom side.

• Along the left side.

• Along the right side.

• Along the top side.

What is the greatest common factor (GCF) of 24 and 36 using the ladder tool?

• 10

• 8

• 6

• 12

How can you remember the method to find the least common multiple (LCM) using the ladder tool?

• It forms a Z shape.

• It forms an X shape.

• It forms an L shape.

• It forms a T shape.

What is the simplified fraction of 24/36 using the ladder tool?

• 3/4

• 2/3

• 4/5

• 1/2