1. Comparing and Ordering Fractions
Lesson 3-7

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
> 4 6
6 x 4 = 24
20 > 18
x 4
x 6 20 18 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
<
9, 18, 27, 36, 45 9 12
12, 24, 36, 48, 60
20 < 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 8 5 4
x 8
x 5
x 10 15 16 10 40 40 40
8, 16, 24, 32, 40, 48
1/4 < 3/8 < 2/5
5, 10, 15, 20, 25, 30, 35, 40
4, 8, 12, 16, 20, 24, 28, 32, 36, 40

7. Homework Time