Adding and Subtracting Fractions - Unlike - Clark.ppt

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2. We need a common
denominator to add
these fractions.

3. 7, 14, 21, 28, 35…
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
We need a common
denominator to add
these fractions.

4. 7, 14, 21, 28, 35…
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
The first number IN COMMON
that appears on both lists
becomes the common denominator

5. x 2
x 2
X 7
x 7
7
6
7 + 6 = 13
13

6. We need a common
denominator to add
these fractions.
5, 10, 15, 20, 25, 30, 35, 40, 45
7, 14, 21, 28, 35, 42, 49, 56, 63

7. x 7
x 7
X 5
x 5
15
7
15 + 7 = 22
22

8. We need a common
denominator to add
these fractions.
7, 14, 21, 28, 35, 42, 49, 56, 63
8, 16, 24, 32, 40, 48, 56, 64, 72

9. x 7
x 7
x 8
x 832
21
32 + 21 = 53
53

10. We need a common
denominator to add
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27
5, 10, 15, 20, 25, 30, 35, 40, 45

11. X 3
x 5
x 5
x 3
9
10
9 + 10 = 19
19

12. We need a common
denominator to add
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33
11, 22, 33, 44, 55, 66, 77…

13. x 11
x 11
X 3
x 315
22
15 + 22 = 37
37

14. We need a common
denominator to add
these fractions.
3, 6, 9, 12, 15, 18, 21, 24, 27
6, 12, 18, 24,…

15. x 1
x 1
X 2
x 24
1
4 + 1 = 5
5

16. We need a common
denominator to add
these fractions.
11, 22, 33, 44, 55, 66, 77…
6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72

17. x 11
x 11
X 6
x 6
18
11
29
18 + 11 = 29

18. We need a common
denominator to add
these fractions.

19. We need a common
denominator to add
these fractions.
9, 18, 27, 36, 45, 54, 63, 72, 81
5, 10, 15, 20, 25, 30, 35, 40, 45

20. 9, 18, 27, 36, 45, 54, 63, 72, 81
5, 10, 15, 20, 25, 30, 35, 40, 45
The first number IN COMMON
that appears on both lists
becomes the common denominator

21. x 5
x 5
x9
x 9
36
35
36 + 35 = 71
71
36 + 35 = 71

22. We need a common
denominator to add
these fractions.
12, 24, 36, 48, 60, 72, 84, 96
8, 16, 24, 32, 40, 48, 56, 64, 72, 79, 80, 88, 96

23. x 3
x 3
x 2
x 2
19
10 + 9 = 19
9
10

24. 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
We need a common
denominator to
subtract a fraction
from another.
11, 22, 33, 44, 55, 66, 77…

25. x 5
x 5
x 11
x 11
4
15 - 11 = 4
15
11

26. We need a common
denominator to
subtract one fraction
from another.
2, 4, 6, 8, 10, 12, 14, 16, 18, 20 …
10, 20, 30…

27. x 1
x 1
x 5
x 5
2
5 – 3 = 2
5
3

28. Try These
A
F
EB
C
D

29. 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.

30. Try These
A
F
EB
C
D
17
27
19
20
10
9
41
28
26
21
13
12