Transcript Fraction IX Least Common Multiple Least Common Denominator

Mr. Coon’s Math Class
The answer to a
multiplication problem.

6 X 6 = 36
7 X 8 = 56
8 X 9 = 72
The product of a whole number
multiplied times any other whole
number.

Some multiples of 6
6, 12, 18, 24, 30, 36, 42
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

A number that is a multiple of
two or more numbers.
Some multiples of 3 & 6
6, 12, 18, 24, 30, 36, 42
8, 16, 24, 32, 40, 48, 56
12, 24, 36, 48, 56, 60
21, 42, 63
10, 20, 30, 40, 50, 60
The smallest common
multiple of a set of two or more
numbers.

5 = 5, 10, 15, 20, 25, 30
6 = 6, 12, 18, 24, 30, 36
3 = 3, 6, 9, 12, 15, 21, 24
8 = 8, 16, 24, 32, 40, 48
4 = 4, 8, 12, 16, 20, 24
8 = 8, 16, 24, 32, 40, 48
6 = 6, 12, 18, 24, 30, 36
8 = 8, 16, 24, 32, 40, 48
4 = 4, 8, 12, 16, 20, 24
10 = 10, 20, 30, 40, 50,
3 = 3, 6, 9, 12, 15, 21,
9 = 9, 18, 27, 36, 45, 54
Find the multiples of each
denominator.

1
5 = 5, 10, 15, 20, 25, 30
1
+10 = 10, 20, 30, 40, 50
Compare the lists of multiples.
Circle the common multiples
between the two lists.

1
5 = 5, 10, 15, 20, 25, 30
1
+10 = 10, 20, 30, 40, 50
Use the lowest common
multiple as the
denominator.

1
5 = 5, 10, 15 ,20 ,25 ,30
1
+10 = 10, 20, 30, 40, 50
This number is also called the
least common denominator.

1
5 = 5, 10, 15 ,20 ,25 ,30
1
+10 = 10, 20, 30, 40, 50
1
2 = 2, 4, 6, 8, 10, 12
1
+ 8 = 8, 16, 24, 32, 40
1
10 = 10, 20, 30, 40,
1
+ 8 = 8, 16, 24, 32, 40
1
10 = 10, 20, 30, 40,
1
+ 4 = 4, 8, 12, 16, 20,
1
2 = 2, 4, 6, 8, 10,
1
+ 4 = 4, 8, 12, 16, 20,
1
2 = 2, 4, 6, 8, 10, 12
1
+ 12 = 12, 24, 36, 48
1
3 = 3, 6, 9, 12, 15
1
+ 4 = 4, 8, 12, 16, 20,
1
3 = 3, 6, 9, 12, 15
1
+ 5 = 5, 10, 15, 20, 25,
1
3 = 3, 6, 9, 12, 15
1
+ 9 = 9, 18, 27, 36, 45,
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.
1
3
1
+ 9
3 will divide evenly into 9,
so 9 is your LCD or LCM.
Using the shortcut, what is the LCD or
LCM?
1
2
1
+ 4
2 will divide evenly into 4,
so 4 is your LCD or LCM.
Using the shortcut, what is the LCD or
LCM?
1 2 will divide evenly into 10,
2 so 10 is your LCD or LCM.
1
+ 10
Using the shortcut, what is the LCD or
LCM?
1 2 will divide evenly into 12,
2 so 12 is your LCD or LCM.
1
+ 12
Using the shortcut, what is the LCD or
LCM?
1
4
1
+ 8
4 will divide evenly into 8,
so 8 is your LCD or LCM.
Using the shortcut, what is the LCD or
LCM?
1
3
1
+ 6
3 will divide evenly into 6,
so 6 is your LCD or LCM.
Using the shortcut, what is the LCD or
LCM?
1 3 will divide evenly into 12,
3 so 12 is your LCD or LCM.
1
+ 12
Using the shortcut, what is the LCD or
LCM?
1 3 will divide evenly into 15,
3 so 15 is your LCD or LCM.
1
+ 15
Using the shortcut, what is the LCD or
LCM?
1
3
1
+ 8
3 will not divide evenly into
8, so find the least common
multiple.