Adding Unlike Fractions

1
Adding Unlike Fractions

• Lesson 5.3

2
Check the Denominators

• If the denominators are already the same, just
  add.
• If the denominators are different, find
  equivalent fractions.
• Use the LCM of the denominators to find your new
  denominator.
• Create the equivalent fractions and add.
• Simplify.

3
Example
3
5
6, 12, 18, 24, 30, 36

9, 18, 27, 36, 45, 54
9
6
15
6
21
x 2
x3


18
18
18
1
1
1
18
21
1
3

6
18
18
3
4
Example 2
7, 14, 21, 28, 35
42, 49, 56
3
1
6, 12, 18, 24, 30
36, 42, 48

7
6
If there are no matches, extend the lists of
multiples further.
18
7
x 6
x 7
25


42
42
42
5
Example 3
12, 24, 36, 48, 60
8
5
15, 30, 45, 60, 75

15
12
x 4
60
1
x 5
40
20



60
60
60
6
Homework Time