1 / 14

Do Now 8/23

Do Now 8/23. Please have your math journals out. I am checking them today. 9 + (-2) = _____ (-8) + _____= -10 11 + _____= -2 Give me 5 non-examples of integers. Fooling the Subtraction Guardian. August 23, 2013. Learning Goal.

marci
Download Presentation

Do Now 8/23

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Do Now 8/23 Please have your math journals out. I am checking them today. • 9 + (-2) = _____ • (-8) + _____= -10 • 11 + _____= -2 • Give me 5 non-examples of integers.

  2. Fooling the Subtraction Guardian August 23, 2013

  3. Learning Goal • I can subtract integers by adding the opposite and explain how it works.

  4. Vocabulary: “Additive Inverse” • Additive Inverse – math word for opposites. • adds to 0. • Example: -1 + 1= 0 • have the same absolute value • Example: |-1| = 1 |1|= 1 “1 is the additive inverse of -1.”

  5. Yesterday • We went to Addition Mountain • Can you use subtraction problems on Addition Mountain?

  6. Only Addition Problems on Addition Mountain • This would be allowed on Addition Mountain: 3 + (-2) = 1 3 + 2 = 5 -2 + 5 = 3 This would not be allowed on Addition Mountain 5 – 8 = -3 4 – (-1) = 3 -9 – 6 = - 15

  7. The Subtraction Guardian • The Subtraction Guardian guards Addition Mountain. • He checks to see if you are an addition problem, or a subtraction problem.

  8. But Subtraction can Transform itself! How? Subtraction is the same as adding the opposite. (Keep Change Opposite)

  9. Can I go to Addition Mountain? 5 + (-3) = (-3) + (-1) = 1 – (-2) = 9 – 4 = Yes Yes No No

  10. Subtracting is Adding the Opposite • 5 – (-3) = • 5 + (-3) = • -5 – (-3) = • -5 + 3 =

  11. What about this? -5 + 3 – (-2) =

  12. Exit Ticket • -5 and 5 are additive __________. • -5 – (-3) + (-1) = ____

More Related