Fractions

By Rosi Barron

Multiples & Least Common Denominators

<--- To Teacher Page

•Fifth Grade Fractions: Multiples & Least Common Denominators

•Tips:

-Teachers, please read through the whole presentation prior to the activity.

-Each activity is meant to be used in addition to your classroom teaching.

-Each activity includes a journal component.

•OBJECTIVE:

TSW list multiples to utilize fractions with Least Common Denominators.

LCD (Least Common Denominator) is the smallest common multiple of two or more denominators.

EXAMPLE: The LCD for 1 and 5 is 12.

4 6Follow these steps:

Step 1: Find the common multiples of your denominators.

4: 4x1=4 4x2=8 4x3=12 4x4=16 4x5=20 4x6=24 4x7=28

6: 6x1=6 6x2=12 6x3=18 6x4=24 6x5=30 6x6=36 6x7=42

What is the smallest common multiple OR the least common multiple, the LCM?

Click here to find out---->

Step 1: Find the common multiples of your denominators.

4: 4x1=4 4x2=8 4x3=12 4x4=16 4x5=20 4x6=24 4x7=28

6: 6x1=6 6x2=12 6x3=18 6x4=24 6x5=30 6x6=36 6x7=42

Is this what you chose?

YOU ARE CORRECT!

Click here to go to step 2 ------>

Step 2: Use the least common multiple as the least common denominator, or LCD.

1 x 2 = 2 1 2

6 x 2 = 12 6 12 (LCD)

3 x 3 = 9 3 9

4 x 3 = 12 4 12 (LCD)

=

=

Click here to see what you can do now ----->

1 x = 1 x =

6 x = 12 (LCD) 6 x 2 = 12 (LCD)

3 x = 3 x =

4 x = 12 (LCD) 4 x 3 = 12 (LCD)

Fill in the

blanks-----

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Add:

1/6 + 3/4 = ___

with LCD 1/6 = 2/12 and 3/4 = 9/12

2/12 + 9/12 =11/12

Compare:

1/6 = OR < OR > 3/4

with LCD 1/6 = 2/12 and 3/4 = 9/12

2/12 < 9/12

Journal what you just reviewed ---->