5'5 Ordering Fractions

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5.5 Ordering Fractions
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Comparing Fractions Using the Least Common
Denominator
To compare 2 fractions, you will need to find a
common denominator.
Compare 5 and 7. 6 9
Ask yourself What is the least common multiple
for both 6 and 9? If you need to list multiples
or do factor trees for both numbers, then do so.
If you guessed 18, you are correct! If you
guessed a higher number, it will work, too.
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Comparing Fractions Continued.
Compare 5 and 7. 6
9
3, so 5 x 3 15
2, so 7 times 2 14
5 and 7 6 18
9 18
15
14


9 times what gives me 18?
6 times what gives me 18?
Because 15 is bigger than 14, 5 is greater.
6
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More Examples when Comparing
Compare 5 and 2. 9 9
Since 5 is greater than 2, 5 is greater.
9
Because the denominators are the same, simply
look at the numerators and compare.
2 x 8 16
5 x 3 15
Because 16 is greater, 2 Is greater
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Compare 5 and 2. 8
3
15
16
24
24


8 x 3 24
3 x 8 24
What is a common denominator for 8 and 3?
Now, set 24 equal to both fractions.
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Ordering Fractions
To order fractions, use the same steps when
comparing.
Order the following fractions 7 , 5 , 2 from
least to greatest.
12 9 3
1st Find a common denominator.
36
2nd Set each fraction equal to 36.
3rd Order them from least to greatest.
x 3
x 4
x 12

• , 7 , 2
• 9 12 3

7 5 2 12 9
3
21
20
24



36
36
36
x 3
x 4
x 12
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Ordering Fractions Cont.
Order the following fractions from least to
greatest.
9, 17 , 4 10 20 5
Common denominator is.
20
x 2
x 4
9 17 4 10 20 5
18
16


20
20
x 2
x 4
Because 17 is already in 20ths, you keep it the
same. 20
Comparing the numerators in order it would be 4,
17, 9
5 20 10
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Now You Try!
Compare the following fractions.
The common denominator is
x 4
x 5
15
3 and 3 5 4
12


20
20
20
x 4
x 5
3 3 5 4
lt
Order the following fractions 3, 2, 5
4 3 8
The common denominator is.
24
x 6
x 3
x 8
18
3 2 5 4
3 8
16
15



5, 2, 3 8 3 4
24
24
24
x 6
x 8
x 3