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25 Binary Operations

  • Submit homework separately from this workbook and staple all pages together. (One staple for the entire submission of all the unit homework)
  • Start a new module on the front side of a new page and write the module number on the top center of the page.
  • Answers without supporting work will receive no credit.
  • Some solutions are given in the solutions manual.
  • You may work with classmates but do your own work.

Exercise 1

Compute and simplify the following. Show all of the steps. Use the binary operations defined in the “Operations and Properties” section of this book.

a. 5 * 9 b. 4 * 8 c. b * a d. 1 ◊ 5
e. 7 ◊ 4 f. b ◊ a g. 88 ∇ 79 h. m ∇ n
i. b ∇ a j. 6 λ 5 k. 2 λ 7 l. b λ a
m. 8 [latex]\dagger[/latex] 1 n. 4 [latex]\dagger[/latex] 6 o. b [latex]\dagger[/latex] a p. 8 @ 5
q. 9 @ 4 r. b @ a s. 6 Θ 7 t. 2 Θ 5
u. b Θ a v. 3 [latex]\otimes[/latex] 8 w. 5 [latex]\otimes[/latex] 6 x. b [latex]\otimes[/latex] a
y. 7 ⊥ 8 z. 3 ⊥ 2 aa. b ⊥ a

Exercise 2

Simplify each of the following. Show each step.

a. 3 * (4 * 2) b. 3 @ (5 @ 2) c. 3 ∇ (5 ∇ 2)

Exercise 3

Compute the following, using the definitions for the operations defined in the “Operations and Properties” section of this book. Show each step.

a. (1 [latex]\otimes[/latex] 2) Θ 7 b. (3 * 1) ◊ c c. (8 ∇ 5) λ 6
d. 7 [latex]\otimes[/latex] (6 ◊ 13) e. 5 * (2 Θ 2) f. 8 ∇ (5 λ 6)

Exercise 4

Suppose that a number system uses only the symbols a, b, c, d, and the operation Ψ.  The basic facts are illustrated in the table.

Ex.    A Ψ C = B     or    D Ψ B = B

Ψ A B C D
A C D B A
B D A C B
C B C B C
D A B C D
a)  Is the system closed? Why?

b)  Is the operation commutative? Why?

c)  Does the operation have an identity? If so, what is it?

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Math for Elementary Teachers Copyright © by Elizabeth Kelly. All Rights Reserved.