1. DO NOW:
Think back to the Elimination Game you played to answer the questions.
What was the result when both chips were the same color?
What was the result when the chips were opposite colors?

2. Students will develop formal rules
Lesson 2-2/3b: Adding and Subtracting Integers    
Goal:
Students will develop formal rules
for
adding integers.

3. In the following table, model each expression using "chips"
In the following table, model each expression using "chips". Record the result of performing the given operation.
Expression
8 – 5
8 + (-5)
Model
Result

4. Expression -8 + 5 -8 – (-5) Model Result
Notice in both examples above, the expression with two symbols in between the numbers can be rewritten using a single symbol. This makes the expression much easier to simplify when using the number line or "chip elimination" methods.

5. While the end result is the same regardless of the way we write it, we usually avoid using double symbols in between as in 8+(-5) or -8-(-5). We can use the following rules to help us rewrite the expressions with only 1 symbol.
Original Symbols
IN BETWEEN
Simplified
+ & + Or
- & - +
+ & -
- & + -

6. Example A: Simplifying Expressions Rewrite each expression so there is only one operation symbol.
-2-(-6)
(-4)
3. 7+(-5)
(-4)
(-1)
– (-1)
7. -7 – 8
– 1
(+5)

7. Example B: Find the sum -2+(-3)
-2 + (-3)
Rewrite the expression with one symbol in between.
Simplify using the number line or "chips" as a guide.

8. Example C: Find the sum -10+4
There is no need to rewrite the expression because there is already only  one symbol in between.
Simplify using the number line or "chips" as a guide

9. Example D: Find the difference-9-(-2)
-9 – (-2)
rewrite the expression with one symbol in between.
Simplify using the number line or "chips" as a guide.

10. Example E: Find the sum -4-3
-4 - 3
There is no need to rewrite the expression because there is already only  one symbol in between.
Simplify using the number line or "chips" as a guide.