Comparing and Ordering Fractions

1
Comparing and Ordering Fractions

• EQ How do we compare and order fractions?

Ch 4 Lesson 7
2
Strategy

• Make sure the denominators are the same.
• Compare the numerators.

• If the denominators are not the same, then
  rewrite the fractions using a common denominator.
  
• The new fractions should be equivalent to the
  original fractions.

3
Writing Equivalent Fractions

• One way to find a common denominator is to
  multiply the two original denominators.

5
3
gt
4
6
6 x 4 24
20 gt 18
x 4
x 6
18
20
24
24
4

• Another way to compare fractions is to find the
  LCM of both denominators.
• Use the LCM as the new denominator in the
  equivalent fractions.

7
5
lt
12
9
9, 18, 27, 36, 45
12, 24, 36, 48, 60
20 lt 21
x 3
x 4
20
21
36
36
5
Ordering Fractions

• Find the LCM of the denominators.
• Use the LCM to write equivalent fractions.
• Put the fractions in order using the numerators.

6
Example - Order from Least to Greatest
3
2
1
5
8
4
x 8
x 5
x 10
15
16
10
40
40
40
8, 16, 24, 32, 40, 48
1/4 lt 3/8 lt 2/5
5, 10, 15, 20, 25, 30, 35, 40
4, 8, 12, 16, 20, 24, 28, 32, 36, 40
7
Homework Time