Chapter 1 Re-Assessment

Name (First and Last)

Period

• Period 1
• Period 4

Decide if the set B={odd numbers} is closed under addition.

• Closed
• Not Closed

Justify your answer to Question 1. Use a detailed explanation OR a counterexample, as appropriate.

Decide if the set A={-1, 0, 1} is closed under multiplication.

• Closed
• Not Closed

Justify your answer to Question 2. Use a detailed explanation OR a counterexample, as appropriate.

Consider the operation @ defined by a@b = a + b - 2. Is the set {0, 1, 2} closed under this operation?

• Closed
• Not Closed

Justify your answer to Question 3. Use a detailed explanation OR a counterexample, as appropriate.

Which lockers will remain open? List them by their number.

Why are these the lockers that will be left open?