Fraction IX Least Common Multiple Least Common Denominator

Fraction IXFraction IXLeast Common Least Common Multiple Least Multiple Least

Common DenominatorCommon Denominator

ProductProduct

The answer to a The answer to a multiplication problem.multiplication problem.

6 X 6 = 36

What is the product?What is the product?

7 X 8 = 56

What is the product?What is the product?

8 X 9 = 72

MultipleMultiple

The product of a whole number The product of a whole number multiplied times any other whole multiplied times any other whole number.number.

Some multiples of 6 6, 12, 18, 24, 30, 36, 42

Name some multiples of Name some multiples of 55

5, 10, 15, 20, 25, 30, 35


7, 14, 21, 28, 35, 42, 49


4, 8, 12, 16, 20, 24, 28


9, 18, 27, 36, 45, 54, 63

Common MultipleCommon Multiple

A number that is a A number that is a multiple of two or more multiple of two or more numbers.numbers.

Some multiples of 3 & 6

6, 12, 18, 24, 30, 36, 42

What are some Common What are some Common Multiples for 2 & 8?Multiples for 2 & 8?

8, 16, 24, 32, 40, 48, 56


12, 24, 36, 48, 56, 60


21, 42, 63


10, 20, 30, 40, 50, 60

Least Common MultipleLeast Common Multiple

The smallest common The smallest common multiple of a set of two or multiple of a set of two or more numbers.more numbers.

6 = 6, 12, 18, 24, 30, 36

5 = 5, 10, 15, 20, 25, 30

What is the Least What is the Least Common Multiple of 3 & Common Multiple of 3 &

88

8 = 8, 16, 24, 32, 40, 48 3 = 3, 6, 9, 12, 15, 21, 24


88

8 = 8, 16, 24, 32, 40, 48 4 = 4, 8, 12, 16, 20, 24


88

8 = 8, 16, 24, 32, 40, 48 6 = 6, 12, 18, 24, 30, 36


1010

10 = 10, 20, 30, 40, 50, 4 = 4, 8, 12, 16, 20, 24


99

9 = 9, 18, 27, 36, 45, 54 3 = 3, 6, 9, 12, 15, 21,

Let’s watch a short video Let’s watch a short video to review!to review!

To Add or Subtract To Add or Subtract Fractions With Unlike Fractions With Unlike

DenominatorsDenominators

Find the multiples of Find the multiples of each denominator.each denominator.

1= 5, 10, 15, 20, 25, 30

1= 10, 20, 30, 40, 50+

5

10


DenominatorsDenominators Compare the lists of multiples. Compare the lists of multiples.

Circle the common multiples Circle the common multiples between the two lists.between the two lists.

15 = 5, 10, 15, 20, 25, 301

10 = 10, 20, 30, 40, 50+



Use the lowest common Use the lowest common multiple as the denominator.multiple as the denominator.

15 = 5, 10, 15 ,20 ,25 ,301

10 = 10, 20, 30, 40, 50+



This number is also called the This number is also called the least common denominator.least common denominator.

15 = 5, 10, 15 ,20 ,25 ,301

10 = 10, 20, 30, 40, 50+

Find the Least Common Find the Least Common Denominator or Least Common Denominator or Least Common

MultipleMultiple

12 = 2, 4, 6, 8, 10, 1218 = 8, 16, 24, 32, 40+


MultipleMultiple

110 = 10, 20, 30, 40, 18 = 8, 16, 24, 32, 40+


MultipleMultiple

110 = 10, 20, 30, 40, 14 = 4, 8, 12, 16, 20, +


MultipleMultiple

12 = 2, 4, 6, 8, 10, 14 = 4, 8, 12, 16, 20, +


MultipleMultiple

12 = 2, 4, 6, 8, 10, 12 112 = 12, 24, 36, 48 +


MultipleMultiple

13 = 3, 6, 9, 12, 15 14 = 4, 8, 12, 16, 20, +


MultipleMultiple

13 = 3, 6, 9, 12, 15 15 = 5, 10, 15, 20, 25, +


MultipleMultiple

13 = 3, 6, 9, 12, 15 19 = 9, 18, 27, 36, 45, +

Shortcut for Finding the Least Shortcut for Finding the Least Common Denominator or Least Common Denominator or Least


1319+

Check to see if the smaller denominator divides evenly into the larger denominator.If it does, use the larger denominator for your LCD or LCM.

3 will divide evenly into 9, so 9 is your LCD or LCM.



1214+

Using the shortcut, what is the LCD or LCM?




12110+





12112+





1418+





1316+





13112+





13115+





1318+


3 will not divide evenly into 8, so find the least common multiple.

Fraction IX Least Common Multiple Least Common Denominator

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