Adding Fractions
+
+ =
+ =
+ =
4
3
+ =
4
3
+
+ =
4
3
4
1
+
+ =
4
3
4
1
+ =
+ =
4
3
4
1
+ =
4
4
+ =
4
3
4
1
+ =
4
4
1
Same
denominators: add
the numerators!
+
+ =
+ =
+ =
+ =
8
5
+ =
8
5
+
+ =
8
5
8
2
+
+ =
8
5
8
2
+ =
+ =
8
5
8
2
+ =
8
7
+ =
8
5
8
2
+ =
8
7
+ =
8
5
4
1
+ =
8
7
If the denominators
are different, find
equivalent fractions,
then add numerators
+
+
12
5
+
3
1
+
12
5
+
3
1
+
+
12
5
+
3
1
+
+
12
5
+
3
1
+
+
12
5
+
3
1
+
+
12
5
+
3
1
12
5
+
+
12
5
+
3
1
12
5
+
+
+
12
5
+
3
1
12
5
+
12
4
12
5
+
12
4
12
5
+
12
4
=
12
5
+
12
4
12
9
=
12
5
+
12
4
12
9
= =
12
5
+
12
4
12
9
= =
4
3
1. Check denominators
1. Check denominators
2. Find equivalent fractions so
denominators same
1. Check denominators
2. Find equivalent fractions so
denominators same
3. Add numerators
1. Check denominators
2. Find equivalent fractions so
denominators same
3. Add numerators
4. Cancel down if needed
1. Check denominators
2. Find equivalent fractions so
denominators same
3. Add numerators
4. Cancel down if needed
5. Pull...
Your turn…
10
3
5
2

4
3
8
7

10
7
10
3
10
4
10
3
5
2

4
3
8
7

10
7
10
3
10
4
10
3
5
2

8
5
1
8
13
8
6
8
7
4
3
8
7

Sometimes, you
have to change both
denominators…
5
4
4
3

5
4
4
3

5
4
4
3

You need a number
that is a multiple of
both 4 and 5…
5
4
4
3
 =
20
?
20
?

5
4
4
3
 =
20
?
20
?

=
20
16
20
15

5
4
4
3
 =
20
?
20
?

=
20
16
20
15
 =
20
31
5
4
4
3
 =
20
?
20
?

=
20
16
20
15
 =
20
31
=
20
11
1
1. Check denominators
1. Check denominators
2. Find ‘common
denominator’ (LCM)
1. Check denominators
2. Find ‘common
denominator’ (LCM)
3. Add numerators
1. Check denominators
2. Find ‘common
denominator’ (LCM)
3. Add numerators
4. Cancel down if needed
1. Check denominators
2. Find ‘common
denominator’ (LCM)
3. Add numerators
4. Cancel down if needed
5. Pull out the whole ...
Your turn…
4
3
6
1

3
2
4
1

12
11
12
8
12
3
3
2
4
1

4
3
6
1

12
11
12
9
12
2
4
3
6
1

12
11
12
8
12
3
3
2
4
1

Sometimes, you
have to add fractions
larger than one…
3
2
1
2
1
2 
I suggest making
these fractions
‘top heavy’.
3
1
1
2
1
2 
3
1
1
2
1
2  =
3
4
2
5

3
1
1
2
1
2  =
3
4
2
5

6
8
6
10
=
3
1
1
2
1
2  =
3
4
2
5

6
8
6
10
=
= 6
18
3
1
1
2
1
2  =
3
4
2
5

6
8
6
10
=
= 6
18
= 3
Now find an exercise in
the book or a work-
sheet and practice!
Upcoming SlideShare
Loading in …5
×

Adding Fractions: traditional approach

9,717 views

Published on

This slide show covers adding two fractions with the same denominator, adding two fractions with one denominator that is a factor of the other, and, finally adding fractions with different denominators. There are a small number of questions for a class to complete as a 'check on learning' during the presentation. I'm assuming the class have access to a textbook or other collection of problems for use after the presentation.

This slideshare version is pretty dry. I usually include a visual 'starter' image of some kind, often a funny sign or joke or screen grab of a news article.

Published in: Education
  • Great PP, check page 70, there is a miscalculation.

    Thanks for sharing your content.
    God Bless.
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

Adding Fractions: traditional approach

  1. 1. Adding Fractions
  2. 2. +
  3. 3. + =
  4. 4. + =
  5. 5. + = 4 3
  6. 6. + = 4 3 +
  7. 7. + = 4 3 4 1 +
  8. 8. + = 4 3 4 1 + =
  9. 9. + = 4 3 4 1 + = 4 4
  10. 10. + = 4 3 4 1 + = 4 4 1
  11. 11. Same denominators: add the numerators!
  12. 12. +
  13. 13. + =
  14. 14. + =
  15. 15. + =
  16. 16. + = 8 5
  17. 17. + = 8 5 +
  18. 18. + = 8 5 8 2 +
  19. 19. + = 8 5 8 2 + =
  20. 20. + = 8 5 8 2 + = 8 7
  21. 21. + = 8 5 8 2 + = 8 7
  22. 22. + = 8 5 4 1 + = 8 7
  23. 23. If the denominators are different, find equivalent fractions, then add numerators
  24. 24. +
  25. 25. + 12 5 + 3 1
  26. 26. + 12 5 + 3 1
  27. 27. + + 12 5 + 3 1
  28. 28. + + 12 5 + 3 1
  29. 29. + + 12 5 + 3 1
  30. 30. + + 12 5 + 3 1 12 5
  31. 31. + + 12 5 + 3 1 12 5 +
  32. 32. + + 12 5 + 3 1 12 5 + 12 4
  33. 33. 12 5 + 12 4
  34. 34. 12 5 + 12 4 =
  35. 35. 12 5 + 12 4 12 9 =
  36. 36. 12 5 + 12 4 12 9 = =
  37. 37. 12 5 + 12 4 12 9 = = 4 3
  38. 38. 1. Check denominators
  39. 39. 1. Check denominators 2. Find equivalent fractions so denominators same
  40. 40. 1. Check denominators 2. Find equivalent fractions so denominators same 3. Add numerators
  41. 41. 1. Check denominators 2. Find equivalent fractions so denominators same 3. Add numerators 4. Cancel down if needed
  42. 42. 1. Check denominators 2. Find equivalent fractions so denominators same 3. Add numerators 4. Cancel down if needed 5. Pull out the whole numbers if needed
  43. 43. Your turn…
  44. 44. 10 3 5 2  4 3 8 7 
  45. 45. 10 7 10 3 10 4 10 3 5 2  4 3 8 7 
  46. 46. 10 7 10 3 10 4 10 3 5 2  8 5 1 8 13 8 6 8 7 4 3 8 7 
  47. 47. Sometimes, you have to change both denominators…
  48. 48. 5 4 4 3 
  49. 49. 5 4 4 3 
  50. 50. 5 4 4 3  You need a number that is a multiple of both 4 and 5…
  51. 51. 5 4 4 3  = 20 ? 20 ? 
  52. 52. 5 4 4 3  = 20 ? 20 ?  = 20 16 20 15 
  53. 53. 5 4 4 3  = 20 ? 20 ?  = 20 16 20 15  = 20 31
  54. 54. 5 4 4 3  = 20 ? 20 ?  = 20 16 20 15  = 20 31 = 20 11 1
  55. 55. 1. Check denominators
  56. 56. 1. Check denominators 2. Find ‘common denominator’ (LCM)
  57. 57. 1. Check denominators 2. Find ‘common denominator’ (LCM) 3. Add numerators
  58. 58. 1. Check denominators 2. Find ‘common denominator’ (LCM) 3. Add numerators 4. Cancel down if needed
  59. 59. 1. Check denominators 2. Find ‘common denominator’ (LCM) 3. Add numerators 4. Cancel down if needed 5. Pull out the whole numbers if needed
  60. 60. Your turn…
  61. 61. 4 3 6 1  3 2 4 1 
  62. 62. 12 11 12 8 12 3 3 2 4 1  4 3 6 1 
  63. 63. 12 11 12 9 12 2 4 3 6 1  12 11 12 8 12 3 3 2 4 1 
  64. 64. Sometimes, you have to add fractions larger than one…
  65. 65. 3 2 1 2 1 2  I suggest making these fractions ‘top heavy’.
  66. 66. 3 1 1 2 1 2 
  67. 67. 3 1 1 2 1 2  = 3 4 2 5 
  68. 68. 3 1 1 2 1 2  = 3 4 2 5  6 8 6 10 =
  69. 69. 3 1 1 2 1 2  = 3 4 2 5  6 8 6 10 = = 6 18
  70. 70. 3 1 1 2 1 2  = 3 4 2 5  6 8 6 10 = = 6 18 = 3
  71. 71. Now find an exercise in the book or a work- sheet and practice!

×