Unit 1. Day 4.
Please get out paper for today’s lesson Name Date Period -------------------------------------------------------- Topic: Adding & “Addtracting” with large integers [& number line] 7.NS.A.1 Apply and extend previous understandings of addition and subtraction to add and subtract rational numbers (fractions)
Today’s Lesson 1) Quick clarification Review: Add/Subtract with larger integers 3) “Additive Inverse” 4) Arrow method
+ + −−−−−−− −−−−−−− −−−−−−− 4−7 ++++ 4− 7 ++++ 4− 7 + ++++ 4−−7 4− −7 4− 7 + ++++ −−−−−−− + + 4−−7 4− −7 ++++ ++++ +++++++ +++++++
Please get out the assignment from last class. Please get out your notes from yesterday. Please complete the quiz, and write your answers in the answer box
Today’s Lesson 1) Quick clarification Review: Add/Subtract with larger integers 3) “Additive Inverse” 4) Arrow method
Example A: + 67−98= − − 9 8 − 6 7 3 31 1 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Same signs:Add and keep the sign Different signs:Subtract and keep the "larger" sign
Example B: − −49−37= − − 1 4 9 + 3 7 8 86 6 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Same signs:Add and keep the sign Different signs:Subtract and keep the "larger" sign
Example C: + 61+36= + + 6 1 3 6 + 9 97 7 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++++++++++++++++++++++++++++ Same signs:Add and keep the sign Different signs:Subtract and keep the "larger" sign
− −38+45= + + 4 5 3 8 Example D: 7 Same signs:Add and keep the sign 1 − 3 8 7 7 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− +++++++++++++++++++++++++++++++++++++++++++++ Same signs:Add and keep the sign Different signs:Subtract and keep the "larger" sign
83+29= 58−87= −27+45= −69−37= Example E*: Example F*: Example G*: Example H*:
Example E*: + 83+29= + + 1 8 3 2 9 + 1 1 112 2
Example F*: + 58−87= − − 7 1 8 7 − 5 8 2 2 9 9
Example G*: − −27+45= + + 3 4 5 1 − 2 7 1 1 8 8
Example H*: − −69−37= − − 1 6 9 + 3 7 106 1 0 6
Please get out the assignment from last class. Please get out your notes from yesterday. Please complete the quiz, and write your answers in the answer box
Today’s Lesson 1) Quick clarification Review: Add/Subtract with larger integers 3) “Additive Inverse” 4) Arrow method
The Additive Inverse 7 spaces −7 7 spaces
Additive opposite inverse of a number −7 6 + −6 7
Please get out the assignment from last class. Please get out your notes from yesterday. Please complete the quiz, and write your answers in the answer box
Today’s Lesson 1) Quick clarification Review: Add/Subtract with larger integers 3) “Additive Inverse” 4) Arrow method
Example I: Suppose you received $10 from your grandmother for your birthday. You spent $4 on snacks. i) How would you write an equation to represent the situation? 10 − 4 = 6 10 + −4 = 6 ii) How would you model your equation on a number line to show your answer?
"𝑎𝑑𝑑𝑖𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑚𝑢𝑡𝑎𝑡𝑖𝑣𝑒" Example J: Using a number line, model the expression: 3+ −2 What can you say about the sum of −2+3 and 3+(−2)? Does order matter when adding numbers? Why or why not? 𝑁𝑜 "𝑎𝑑𝑑𝑖𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑚𝑢𝑡𝑎𝑡𝑖𝑣𝑒"
Example K*: −6+4 Example L*: 3+ −8
𝑌𝑒𝑠 𝑁𝑜, 𝑏𝑒𝑐𝑎𝑢𝑠𝑒 𝑎𝑑𝑑𝑖𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑚𝑢𝑡𝑎𝑡𝑖𝑣𝑒 5 −2 +3=6 5+ −2 +3=6 Example M: 5 −2 +3=6 5+ −2 +3=6 Would the sum change if we changed the order in which we add the numbers, for example, (−2)+3+5? 𝑁𝑜, 𝑏𝑒𝑐𝑎𝑢𝑠𝑒 𝑎𝑑𝑑𝑖𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑚𝑢𝑡𝑎𝑡𝑖𝑣𝑒 𝑌𝑒𝑠 Would the diagram change? If so, how?