Multiples and LCD H.W.

What is the Least Common Multiple (LCM) of 2 and 4?

2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20

4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40

(Hint! Look for the first number that is the same on both lists!)

• The LCM is 4

• The LCM is 8

• The LCM is 12

• The LCM is 16

Answer explanation

The LCM of 2 and 4 is 4! It's the first multiple that is the same on both lists and has the factors 2 and 4!

Fun fact! All the multiples of 4 are common multiples of 2 because all the multiples of 4 are even numbers!

Challenge!

What is the LCM of 12 and 20?

• The LCM is 20

• The LCM is 40

• The LCM is 60

• The LCM is 80

Answer explanation

The LCM of 12 and 20 is also 60!

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Tags

CCSS.3.NF.A.3D

What is the Least Common Denominator (LCD) of the fractions 1/2 and 1/4?

(Hint! Find the Least Common Multiple (LCM) of 2 and 4 )

• The LCD is 16

• The LCD is 12

• The LCD is 8

• The LCD is 4

Answer explanation

The least common multiple of 2 and 4 was 4!

So the least common denominator of 1/2 and 1/4 is also 4!

What is the LCM of 10 and 12?

(Make a lists of multiples for 10 and 12 and look for the first multiple that is the same!)

• The LCM is 20

• The LCM is 40

• The LCM is 60

• The LCM is 80

Answer explanation

The LCM for 10 and 12 is 60!

Fun fact! If you are trying to find the least common multiple of a number and 10, look for the first multiple of the other number that ends with a zero!

What is the Least Common Multiple (LCM) of 4 and 5?

(Hint! Make a list of multiples by counting by 4 and 5 and see what is the first multiple that is the same on both lists)

• The LCM is 20

• The LCM is 40

• The LCM is 25

• The LCM is 36

Answer explanation

The LCM of 4 and 5 is 20! It's the first multiple on both lists and has the factor 4 and 5.

Practice time!

What is the least common denominator (LCD) for 2/3 and 2/5?

(Hint! Think about least common multiple (LCM) of the denominators )

• The LCD is 9

• The LCD is 12

• The LCD is 15

• The LCD is 18

What is the least common multiple of 6 and 12?

• 2

• 12

• 24

• 36

Choose the larger fraction.

• 4/9

• 5/9

Tags

CCSS.3.NF.A.3D

What is the LCM of 3 and 6?

(Hint! Make a list of multiples for 3 and 6 and see what is the first common multiple on both lists!)

• The LCM is 3

• The LCM is 6

• The LCM is 9

• The LCM is 12

Answer explanation

The LCM of 3 and 6 is 6!

Fun fact! All the multiples of 6 are also common multiples of 3!