2.2+Inventing+a+New+Model

Nity Gogia April 6th, 2009 Block 7B.

Big Idea:
Negative numbers help us to model many real world situations.

Essential Question:
How can I add integers?


 * Problem 2.2 - Inventing a New Model**

1. -8 + -7 2. -8 + +7 3. +8 + -7 4. +8 + +7
 * A. Use a chip board and black and red chips to find each sum. Draw a series of chip boards to illustrate your work.

B. Find two combinations of black and red chips that will simplify to represent the given integer. Draw a series of chip boards to prove that each combination works. 1. -3 2. +5

C. Write each combination you found in part B as an addition sentence.**


 * Problem 2.2 Follow Up

1. What integer added to -8 gives a sum of -4?

2. Give two integers with a sum that is less than either of the two integers.

3. Give two integers with a sum that is greater than either of the two integers.

4. Use Conrado's method to compute the following sums in your head. A. +9 + +7 B. -80 + +50 C. +35 + -27 D. -8 + -5**