22 Chapter 1 Problem Solving

Activity: Logical Reasoning

Materials: Pencil

Learning Objective:Students look at a logical argument to decide whether the reasoning is valid or fl awed. Students should only use the given information. They should nottry to reason whether the conclusionis true or false in real life. The goal isto decide whether the conclusion followslogically from the given information.

Name _____________________________

Use the given information to decide whether the conclusion is valid or fl awed. Circle the correct answer. Explain your reasoning.

Given information Conclusion

1. Everyone in Tyrone’s class got an A Therefore, Diane got an A Valid Flawed on the math test. Diane is in on the math test. Tyrone’s class.

2. Everyone in Tyrone’s class got an A Therefore, James did not Valid Flawed on the math test. James is not in get an A on the math test. Tyrone’s class.

3. All rectangles are parallelograms. Therefore, all rectangles Valid Flawed All parallelograms are quadrilaterals. are quadrilaterals.

4. All rectangles are parallelograms. Therefore, all rectangles Valid Flawed All squares are quadrilaterals. are quadrilaterals.

5. If Robert makes this fi eld goal, then Therefore, Robert’s team Valid Flawed Robert’s team will win the game. wins the game. Robert makes the fi eld goal.

6. If Robert makes this fi eld goal, then Therefore, Robert’s team Valid Flawed Robert’s team will win the game. did not win the game. Robert did not make the fi eld goal.

7. Some horses are paints. Therefore, Toby is a horse. Valid Flawed Toby is a paint.

8. All paints are horses. Toby is a paint. Therefore, Toby is a horse. Valid Flawed

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