```Adding & Subtracting Fractions
Teacher Notes:
• Use this presentation to teach the steps
for adding and subtracting fractions with
unlike denominators.
• It is assumed that students have a
thorough understanding of the process for
making equivalent fractions.
opportunities for students to practice
making equivalent fractions.
We need a common
these fractions.
We need a common
these fractions.
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
7, 14, 21, 28, 35…
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
7, 14, 21, 28, 35…
The first number IN COMMON
that appears on both lists
becomes the common denominator
x7
7
X7
x2
6
7 + 6 = 13
x2
13
We need a common
these fractions.
7, 14, 21, 28, 35, 42, 49, 56, 63
5, 10, 15, 20, 25, 30, 35, 40, 45
x5
15
X5
x7
7
x7
15 + 7 = 22
22
We need a common
these fractions.
7, 14, 21, 28, 35, 42, 49, 56, 63
8, 16, 24, 32, 40, 48, 56, 64, 72
x8
32
x8
x7
21
32 + 21 = 53
x7
53
We need a common
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27
5, 10, 15, 20, 25, 30, 35, 40, 45
x3
9
X3
x5
9 + 10 = 19
10
x5
19
We need a common
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33
11, 22, 33, 44, 55, 66, 77…
x3
15
X3
x 11
22
15 + 22 = 37
x 11
37
We need a common
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27
6, 12, 18, 24,…
x2
4
X2
x1
1
x1
5
4+1=5
We need a common
these fractions.
11, 22, 33, 44, 55, 66, 77…
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72
x6
18
X6
x 11
11
18 + 11 = 29
x 11
29
We need a common
these fractions.
We need a common
these fractions.
5, 10, 15, 20, 25, 30, 35, 40, 45
9, 18, 27, 36, 45, 54, 63, 72, 81
5, 10, 15, 20, 25, 30, 35, 40, 45
9, 18, 27, 36, 45, 54, 63, 72, 81
The first number IN COMMON
that appears on both lists
becomes the common denominator
x9
36
x9
x5
35
x5
71
36 + 35 = 71
We need a common
these fractions.
12, 24, 36, 48, 60, 72, 84, 96
8, 16, 24, 32, 40, 48, 56, 64, 72, 79, 80, 88, 96
x2
10
x2
x3
9
10 + 9 = 19
x3
19
We need a common
denominator to
subtract a fraction
from another.
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
11, 22, 33, 44, 55, 66, 77…
x5
15
x5
x 11
11
15 - 11 = 4
x 11
4
We need a common
denominator to
subtract one fraction
from another.
2, 4, 6, 8, 10, 12, 14, 16, 18, 20 …
10, 20, 30…
x5
5
x5
x1
3
5–3= 2
x1
2
Try These
A
D
B
E
C
F
• Each click on the next slide
• If you discover an incorrect
Try These
17
27
D
10
9
B
13
12
E
41
28
C
19
20
F
26
21
A
```