1. Unit 2. Day 4.

2. Please get out paper for today’s lesson
Name
Date
Period
Topic: Adding & Subtracting Rational Numbers
7.NS.A.1 Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers (fractions)

3. 4th, 5th, 6th Grade

4. Example -: Add or subtract. Write in simplest form.
4 8
1 2
3+1
2∙2 = = = = 8 8
2∙2∙2 4 8 2 2 2 4 2 2

5. 7th Grade

6. Example A: Add or subtract. Write in simplest form.
23 24 − 39 24
−16 24
23−39
− 2 3
− 2∙2∙2∙2 = = = = 24 24
2∙2∙2∙3 24 16 4 6 4 4 2 2 3 2 2 2 2 2

7. − 11 16 − 1 16 Add or subtract. Write in simplest form. Example B*:
− − −7 12
Example C*:
5 1 6 −6 5 6
31 6
41 6
Example D*: −

8. Example B*: Add or subtract. Write in simplest form.
− − 1 16
−12 16
−11−1
− 3 4
−2∙2∙3 = = = = 16 16
2∙2∙2∙2 12 16 4 4 3 4 2 2 2 2 2 2

9. Example C*: Add or subtract. Write in simplest form.+
− − − 7 12
− − −7 12
−10 12
− 5 6
−17+7
−2∙5 = = = = 12 12
2∙2∙3 12 10 3 4 2 5 2 2

10. 10 6 3 2 5 2 Example D*: Add or subtract. Write in simplest form.
5 1 6 −6 5 6
31 6
41 6 −
31−41
−10 6
−2∙5
− 5 3 = = = =
2∙3 6 6
−1 2 3 = 10 6 2 5 2 3

12. Uncommon Denominators

13. Example E:
5 14 − 5 8
20 56
35 56
−15 56
−1∙3∙5
− 15 56 = − = = = 14 8
2∙2∙2∙7
5 14 20 56
5 8 35 56   : 14 , 28 , 42 , 56 , 70 , 84 , 98 ,
112 ,
126 ,
140 ,
154 , : 8 , 16 , 24 , 32 , 40 , 48 , 56 , 64 , 72 ,

14. −
Example F:
− − 3 9
Example G:

15. Example F*: − −
−10 24
−1∙2∙5
−5 12 = = = = 8 24
2∙2∙2∙3
− 5 8
− 24 15
5 24 5 24   : 8 , 16 , 24 , 32 , 40 , 48 , 56 , 64 , 72 , 80 , 88 , 96 ,
104 : 24 , 48 , 72 , 96 ,
120 ,
144 ,
168 ,
192 ,
216 ,
240

16. : : : : Example G*: − 6 8 − 72 54  − 6 8 + − 3 9 − 13 12 −13 12 = = 8
− 72 54 
− − 3 9 +
− 54 72
− 24 72
−78
−1∙2∙3∙13
− 13 12
−13 12 = = 72 = = 8 9
2∙2∙2∙3∙3
− 3 9
− 72 24 
−1 1 12 : 8 , 16 , 24 , 32 , 40 , 48 , 56 , 64 , 72 , 80 : 9 , 18 , 27 , 36 , 45 , 54 , 63 , 72 +
− 1 3 +
− 3 4
− 12 9
− 3 4
− 6 8
− 3 9
− 9 12
− 13 12
−13 12
− 4 12 = =  4 3
− 1 3
− 12 4 
−1 1 12 : 4 , 8 , 12 , 16 , 20 , 24 : 3 , 6 , 9 , 12

17. 8 16 − 4 32 5 15 − 12 20 − 8 9 − − 5 6 Example H*: Example I*:
Example J*:

18. Example H: +
− 8 9 − − 5 6 −
− 1 18 = = 9 6
5 6 15 18
− 8 9
− 18 16   : 9 , 18 , 27 , 36 , 45 , 54 , 63 , 72 , 81 , 90 , 99 ,
108 ,
117 : 6 , 12 , 18 , 24 , 30 , 36 , 42 , 48 , 54 , 60 , 66 , 72

19. Example I*:
8 16 16 32 
8 16 − 4 32
16 32 − 4 32
12 32
2∙2∙3
3 8 = = = = 16 32
2∙2∙2∙2∙2
4 32 4 32  : 16 , 32 , 48 , 64 , 80 , 96 : 32 , 64 , 96 ,
128
1 2 − 1 8
1 2 4 8
4 8 − 1 8
3 8 = =  2 8 :
1 8 1 8 2 , 4 , 6 , 8 , 10 , 12  : 8 , 16 , 24 , 32

20. Example J*:
5 15 20 60 
5 15 − 12 20
20 60 − 36 60
−16
−4 15
−1∙2∙2∙2∙2 = = 60 = = 15 20
2∙2∙3∙5
12 20 36 60  : 15 , 30 , 45 , 60 , 75 , 90 : 20 , 40 , 60 , 80
5 15
1 3
9 15
3 5
1 3 5 15
5 15 − 9 15 −4 − = =  15 3 5
3 5 9 15  : 3 , 6 , 9 , 12 , 15 , 18 : 5 , 10 , 15 , 20