Unit 2. Day 4.

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)

4th, 5th, 6th Grade

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

7th Grade

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

− 11 16 − 1 16 Add or subtract. Write in simplest form. Example B*: − 17 12 − −7 12 Example C*: 5 1 6 −6 5 6 31 6 41 6 Example D*: −

Example B*: Add or subtract. Write in simplest form. − 11 16 − 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

Example C*: Add or subtract. Write in simplest form. + − 17 12 − − 7 12 − 17 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 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

Uncommon Denominators

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 ,

− 5 8 + 5 24 Example F: − 6 8 + − 3 9 Example G:

Example F*: − 5 8 + 5 24 − 15 24 + 5 24 −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

: : : : Example G*: − 6 8 − 72 54  − 6 8 + − 3 9 − 13 12 −13 12 = = 8 − 72 54  − 6 8 + − 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

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

Example H: + − 8 9 − − 5 6 − 16 18 + 15 18 − 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

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

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