Do Now 8/23

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 =

12. What about this? -5 + 3 – (-2) =

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