1. Do Now Each of the letters stands for a different digit. The first digit in a number is never zero. Replace the letters so that each sum is correct.

2. Homework Worksheet Need extra help? Book: 2.4

3. Unit 1: Basics of Geometry Day 7: Introduction to Logic

4. Objective To use logical reasoning to make viable arguments and proofs

5. Conditional Statements If….., then….. If….., then….. If it is Saturday, then there is no school. If it is Saturday, then there is no school. p: hypothesis Condition that must be met q: conclusion Can only be concluded if the condition is met What can be concluded if it is Saturday? What can be concluded if there is no school? Is the statement true? There is no school. Nothing, the conditional statement only works in one direction. Yes, on Saturdays, there is no school. You must show it is true in all cases.

6. Conditional Statements Converse Statements Made by switching the hypothesis and conclusion Made by switching the hypothesis and conclusion If it is Saturday, then there is no school. If it is Saturday, then there is no school. If there is no school, then it is Saturday. If there is no school, then it is Saturday. hypothesis conclusion Is the statement true? For a statement to be false, it needs to be false in only one instance…. Provide a counterexample. Sometime it is true, and sometimes it is false. There I no school on Labor Day and it is not a Saturday.

7. Conditional Statements If two angles form a linear pair, then they are supplementary. Identify the hypothesis. Identify the conclusion. Is the statement true? What is the converse of the statement? Is the converse true? Two angles form a linear pair. Two angles are supplementary. Yes, linear pairs are always supp. If two angles are supplementary, then they form a linear pair. Yes, supp. angs. can always form a LP

8. Bi-Conditional Statements …if and only if…. …if and only if…. Two angles will form a linear pair if and only if they are supplementary. Two angles will form a linear pair if and only if they are supplementary. Biconditional statements occur when conditional and converse statements are both true. All definitions are biconditional For example, a right angle measures 90 o Biconditional statements are true forward and backwards

9. Did you meet today’s objective? Why are “if…, then…” statements called conditional statements? How do you determine if a statement is true or false? What is a biconditional statement?