1. Warm Up  Name the property that the following statements demonstrate: 1. (8 + 4) + 3 = 8 + (4 +3 ) 2. -1 2 = -2 3. 4 + 0 = 4  Use Mental math to calculate: 4. 4 + 6 + 23 5. 2 3 100

2. Cornell Notes

3. Deductive Reasoning and Counterexamples Section 1.4 B

4. Objective  TSWBAT  Use deductive reasoning to decide if a statement is true of false.  Use counterexamples to show statements are false.

5. Vocabulary  Equivalent expressions  Deductive reasoning  Counterexample

6. Example 1  What is the simplified form of each expression? A. 4(8n) B. (3 + 5b) + 7 C.

7. Example 2  Is the statement true or false? If false, give a counterexample. A. For all real numbers a and b, a – b = b - a B. For all real numbers a, b, and c, a ● b ● c = a ● c ● b

8. Assignment  Pg. 26-28 # 20-43