Unit 2. Day 10.

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)

Q: What is a rational number? A: A number that can be written as a fraction 𝑝 𝑞 − 5 7 − 5 7 2 3 2 3 −4 5 6 −4 5 6 0.875 0.875 −16. 3 −16. 3 Today: + +

−2.4 + 3 4 −2 1 2 3 4 − 2 1 2 Example A: −2.4 + 3 4 −2 1 2 3 4 − 2 1 2 −2.4 −2.4 − 24 10 3 4 − 5 2 + −2.4 + 0.75 −2.5 −2.5 − 20 48 20 15 − 20 50 + − −48+15−50 20 − −33 1 −50 20 1 3 1 1 2 . 4 1 . 6 5 − 0 . 7 5 + 2 . 5 −4 3 20 −83 = 1 1 . 6 5 . 6 5 . 20 4 4.15 1 5

Which way is better?

−0.8 + 2 3 2 3 Example -: −0.8 − 8 10 2 3 + − 30 24 30 20 + −24+20 30 −4 −2 15 = 30 =

Example -: −0.8 + 2 3 2 3 −0.8 −0.8 + 0.6666666666666… − 7 1 0 . 8 −2 15 − = 0 . 6 7 0 . 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 −0.1 3 0.13 . 1 3

Example B*: + −1 1 6 +4.5 − −2 5 6 −1 1 6 2 5 6 4.5 − 7 6 45 10 17 6 + + − 30 35 30 135 85 30 + + −35+135+85 30 6 1 6 37 6 185 + 85 30 100 = = 30 =

Groups

−5.2− −3.1 +5.2 Example C: Example D: Example E: Example F: 32 + −12 7 8 Example D: 3 1 6 +20.3 − −5 5 6 Example E: 16 20 − −1.8 − 4 5 Example F: S.51 Exercise 2

+ Example C: −5.2− −3.1 +5.2 3.1

Example D*: 32 + −12 7 8 −12 7 8 32 32 1 − 103 8 8 256 − 8 103 256−103 8 153 8 19 1 8 =

+ + 9 29.3 + + Example E*: 3 1 6 +20.3 − −5 5 6 3 1 6 +20.3 − −5 5 6 3 1 6 +20.3 − −5 5 6 3 1 6 +20.3 − −5 5 6 3 1 6 5 5 6 3 1 6 5 5 6 20.3 20.3 19 6 203 10 35 6 + + 19 6 35 6 + 30 95 30 609 175 30 + + 6 54 95+609+175 30 9 + 879 30 293 10 29 3 10 = = = 29.3 29.3

Example F: + 16 20 − −1.8 − 4 5 16 20 − 4 5 1.8 4 5 4 5 + 18 10 − 4 5 18 10 − 4 5 18 10 + 10 8 18 −8 10 10 + + 9 5 1.8 8+18−8 10 1 4 5 26 −8 10 9 5 1 4 5 18 = 10 = =