Unit 2. Day 14.

Please get out paper for today’s lesson Name Date Period -------------------------------------------------------- Topic: Multiplying & Dividing Rational Numbers 7.NS.A.2 Apply and extend previous understandings of multiplication and division and of fractions to multiply and divide rational numbers

∙ Example A: − 7 20 ∙ = = = − 35 100 8 15 8 15 56 2∙2∙2∙7 14 − − 300 8 15 −0.35 8 15 ∙ −0.35 8 15 − 35 100 8 15 − 7 20 56 2∙2∙2∙7 14 ∙ = − = − = − 300 2∙2∙3∙5∙5 75

÷ ÷ Example B: − 7 20 ÷ = = = − = 8 15 − 35 100 8 15 − 7 160 8 15 ÷ −0.35 8 15 Example B: ÷ −0.35 8 15 − 35 100 8 15 − 7 20 8 15 − 7 20 ÷ ÷ − 7 160 2∙2∙2∙2∙2∙5 8 15 = − = − ∙ 20 105 3∙5∙7 32 −1 11 21 = − = 21

0.4÷−1 1 3 Example C*: 8 9 −0.6 Example D*:

÷ ÷ Example C*: − 4 3 ÷ = = = 4 10 − 4 3 2 5 − 4 2∙3 3 2 5 6 − − ∙ 0.4÷−1 1 3 −1 1 3 Example C*: ÷ 0.4 4 10 − 4 3 2 5 − 4 3 2 5 − 4 3 ÷ ÷ − 4 2∙3 3 2 5 6 − = − = − = ∙ 2∙2∙5 10 3 20

∙ Example D*: − 3 5 ∙ = = = − 6 10 8 9 8 9 24 2∙2∙2∙3 8 − − 45 3∙3∙5 8 9 −0.6 8 9 ∙ −0.6 8 9 − 6 10 8 9 − 3 5 24 2∙2∙2∙3 8 ∙ = − = − = − 45 3∙3∙5 15

The Commutative Property 2+3 3+2 2−3 3−2

− 4 25 −0.45 − 4 25 Commutative? −0.45 − 4 25 − 4 25 ∙ −0.45 −0.45 ∙ − 4 25 − 45 100 − 45 100 − 4 25 − 4 25 − 9 20 − 9 20 − 4 25 36 36 ∙ = ∙ = 500 500 2∙2∙3∙3 2∙2∙3∙3 2∙2∙5∙5∙5 2∙2∙5∙5∙5 9 9 125 125

− 4 25 ÷ −0.45 − 4 25 Commutative? −0.45 ÷ − 4 25 − 4 25 ÷ ÷ −0.45 −0.45 − 4 25 − 45 100 − 45 100 − 4 25 − 9 20 − 20 9 − 9 20 − 4 25 − 25 4 − 4 25 80 225 ÷ ∙ = ÷ ∙ = 225 80 3∙3∙5∙5 2∙2∙2∙2∙5 3∙3∙5∙5 2∙2∙2∙2∙5 16 45 = = 0.3 5 2.8125 45 16

(Using Commutative Property of Multiplication) Clever Math (Using Commutative Property of Multiplication)

Example E: 4 ∙ 1 3 ∙ −8 ∙ 9 ∙ − 1 2 1 3 − 1 2 4 −8 9 − 8 1 ∙ ∙ ∙ ∙ 8 2 1 3 ∙ ∙ 4 9 1 4 ∙ 9 9 3 ∙ 4 ∙ 4 3 12 ∙ 4 48

Example F: 1 ÷ 2 3 ∙ −8 ∙ 3 ÷ − 1 2 − 2 1 1 ∙ −8 ∙ 3 3 2 3 2 − 2 1 1 ∙ −8 3 ∙ ∙ ∙ ∙ ∙ − 6 2 −3 ∙ −8 ∙ 3∙ 1 24 ∙ 3∙ 1 72∙ 1 72