Finding the LCM of Fractions

What number could be a common denominator for these two fractions?
2/3   and   3/4

• 3

• 4

• 7

• 12

What number could be a common denominator for these two fractions?
1/5   and   5/6?

• 30

• 11

• 6

• 5

The LCD of 2/3 and 3/5 is _______.

• 15

• 10

• 9

• 6

The LCD of 2/4 and 5/9 is ___________.

• 32

• 36

• 63

• 81

The LCD of 5/8 and 7/12 is ____________.

• 24

• 32

• 16

• 64

Now it's time to use what you have learned about Least Common Multiple (LCM) to find the Least Common Denominator (LCD) of two fractions!

Are you ready to try it out? Pick the image for how you feel.

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

• The LCD is 9

• The LCD is 12

• The LCD is 15

• The LCD is 18

What will the fractions 2/3 and 2/5 look like after you change both denominators to have their LCD? (Hint! Multiply the numerator and denominator of 2/3 and 2/5 by the factors that will change their denominators into 15 )

• 2/3 = 4/15

  2/5 = 3/15

• 2/3 = 5/15

  2/5 = 4/15

• 2/3 = 12/15

  2/5 = 10/15

• 2/3 = 10/15

  2/5 = 6/15