Download Least Common Multiple

Least Common Multiple
Warm Up Exercise
1. Joanne is campaigning for class president and
plans to distribute some campaign materials: 20
flyers and 16 buttons. She wants each classroom to
receive an identical set of campaign materials,
without having any materials left over. What is the
greatest number of classrooms Joanne can
distribute materials to?
2. Serena wants to create snack bags for a trip she is
going on. She has 6 granola bars and 10 pieces of
dried fruit. If the snack bags should be identical
without any food left over, what is the greatest
number of snack bags Serena can make?
Warm Up Exercise
• Joanne is campaigning for class president and
plans to distribute some campaign materials: 20
flyers and 16 buttons. She wants each classroom to
receive an identical set of campaign materials,
without having any materials left over. What is the
greatest number of classrooms Joanne can
distribute materials to?
– 16 – 1, 2, 4, 8, 16
– 20 – 1, 2, 4, 5, 10, 20
GCF: 4 – Joanne can distribute campaign materials
to 4 classrooms
Warm Up Exercise
• Serena wants to create snack bags for a trip she is
going on. She has 6 granola bars and 10 pieces of
dried fruit. If the snack bags should be identical
without any food left over, what is the greatest
number of snack bags Serena can make?
– 6 – 1, 2, 3, 6
– 10 – 1, 2, 5, 10
GCF: 2 – Serena can make 2 snack bags of granola
bars and dried fruit
Lesson Objective
• We can identify the least common
multiple of two whole numbers
Least Common Multiple (LCM)
Vocabulary:
 Multiple – the product of any
quantity and an integer.
 Least Common Multiple – the
least non-zero common multiple
of two or more numbers.
Least Common Multiple (LCM)
When thinking about finding the Least
Common Multiple, or the LCM…
REMEMBER
L…List all the multiples of the
number
C…all terms in common
M…from their list of multiples find the
smallest
Least Common Multiple (LCM)
Important to Remember…
THREE
There are
methods for
finding the Common Multiples of two or
more numbers…
Method 1…Use Multiple Lists
Method 2…Use Prime Factorization
Method 3…Multiply the Numbers***
Least Common Multiple (LCM)
Finding the LCM: Method 1 – Multiple List
Example 1: Find the LCM of 4 and 9.
Step 1: Create a list of multiples for each number
Step 2: Circle the first multiple the numbers have
in common
4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, …
9: 9, 18, 27, 36, 45, 54, 63,…
The LCM of 4 and 9 is 36
Least Common Multiple (LCM)
Finding the LCM: Method 1 – Multiple List
Example 2: Find the LCM of 10 and 12.
Step 1: Create a list of multiple for each number
Step 2: Circle the first multiple the numbers have
in common
10: 10, 20, 30, 40, 50, 60, 70, 80,…
12: 12, 24, 36, 48, 60, 72, 84,…
The LCM of 10 and 12 is 60
Least Common Multiple (LCM)
Finding the LCM: Method 1 – Multiple List
Example 3: Find the LCM of 12 and 16.
Step 1: Create a list of multiple for each number
Step 2: Circle the first multiple the numbers have
in common
Least Common Multiple (LCM)
Finding the LCM: Method 1 – Multiple List
Example 3: Find the LCM of 12 and 16.
Step 1: Create a list of multiple for each number
Step 2: Circle the first multiple the numbers have
in common
12: 12, 24, 36, 48, 60, 72, 84, 96, …
16: 16, 32, 48, 64, 80, 96,…
FYI…there is always more
than one multiple for any
set of numbers
The LCM of 12 and 16 is 48
Least Common Multiple (LCM)
Independent Practice Problems
Directions: Find the LCM for each number set.
1. 6 and 10
2. 2, 4, and 5
3. 4, 6, and 8
Least Common Multiple (LCM)
Independent Practice Problems
Directions: Find the LCM for each number set.
1. 6 and 10
2. 2, 4, and 5
3. 4, 6, and 8
=> 30
Least Common Multiple (LCM)
Independent Practice Problems
Directions: Find the LCM for each number set.
1. 6 and 10
=> 30
2. 2, 4, and 5
=> 20
3. 4, 6, and 8
Least Common Multiple (LCM)
Independent Practice Problems
Directions: Find the LCM for each number set.
1. 6 and 10
=> 30
2. 2, 4, and 5
=> 20
3. 4, 6, and 8
=> 24
Least Common Multiple
• Least Common Multiple Study Jams:
http://studyjams.scholastic.com/studyjams/ja
ms/math/fractions/least-commonmultiple.htm