Adding

1

dding
ubtracting
ractions
2
We need a common denominator to add these
fractions.

3
Count by 2's
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Count by 7's
7, 14, 21, 28, 35
4
x 7
7
Make equivalent fractions.

X 7
6
x 2
Add the numerators


7 6 13
x 2
13
5
We need a common denominator to add these
fractions.

Count by 7's
7, 14, 21, 28, 35, 42, 49, 56, 63
Count by 5's
5, 10, 15, 20, 25, 30, 35, 40, 45
6
x 5
15
Make equivalent fractions.

X 5
x 7
7

Add the numerators

x 7
15 7 22
22
7
We need a common denominator to add these
fractions.
Count by 7's
7, 14, 21, 28, 35, 42, 49, 56, 63
Count by 8's
8, 16, 24, 32, 40, 48, 56, 64, 72
8
32
x 8
Make equivalent fractions.

x 8
21
Add the numerators
x 7

32 21 53

x 7
53
9
We need a common denominator to add these
fractions.

Count by 3's
3, 6, 9, 12, 15, 18, 21, 24, 27
Count by 5's
5, 10, 15, 20, 25, 30, 35, 40, 45
10
x 3
Make equivalent fractions.
9

X 3
Add the numerators
9 10 19
x 5
10


Change to Mixed
x 5
1
19

11
We need a common denominator to subtract a
fraction from another.
-
Count by 5's
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
Count by 11's
11, 22, 33, 44, 55, 66, 77
12
15
x 5
Make equivalent fractions.

x 5
11
x 11
Subtract.

15 - 11 4
-
x 11
4
13
We need a common denominator to subtract one
fraction from another.
-
Count by 2's
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Count by 10's
10, 20, 30
14
5
x 5
Make equivalent fractions.

x 5
Subtract.
3
5 3 2
x 1
-
Simplify

x 1
2
2

2
15
Try These
A
D
E
B
F
C
16
Answers On Next Slide

• Each click on the next slide reveals an answer.
• Check your papers.
• If you discover an incorrect answer, be able to
  explain your mistake.

17
Try These
A
D
B
E
F
C