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7.E: Exercises

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Exercise 7.E.1

Convert 1011011012 to base 10.

Answer

TBD.

Exercise 7.E.2

The tripletown number system use only numbers which are 1 more than some multiples of 3.

  1. Construct a 5×5 tripletown number system of multiplication table with the numbers 1,4,7,10 and 13.
  2. Find the smallest ten prime numbers in the tripletown number system.
  3. Find a number with two different tripletown number system prime factorizations.
  4. Does the Prime divisibility Theorem hold for the tripletown number system? Explain.

Exercise 7.E.3

The Quadritown number system use only numbers which are 1 more than some multiples of 4.

  1. Construct a 5×5 Quadritown number system of multiplication table with the numbers 1,5,9,13 and 17.
  2. Find the smallest ten prime numbers in the Quadritown number system.
  3. Find a number with two different Quadritown number system prime factorizations.
  4. Does the Prime divisibility Theorem hold for the Quadritown number system? Explain.
Answer

 

X

1

5

9

13

17

1

1

5

9

13

17

5

5

25

45

65

85

9

9

45

81

117

153

13

13

65

117

169

221

17

17

85

153

221

289

 

Answer

5, 9, 13, 17, 21, 29, 33, 37, 41, 49

3. Find a number with two different Quadritown prime factorizations.

A solution: (found by trial and error)

Examples

Product

Prime Factorization #1

Prime Factorization

#2

441

(21)(21)

(9)(49)

1089

(33)(33)

(9)(121)

2205

(5)(21)(21)

(5)(9)(49)

3249

(57)(57)

(9)(361)

 

Prime divisibility is defined as follows:

Let p be a prime and let a and b be integers. If p ∣(ab)then p∣a or p∣b.

Thus, prime divisibility does not hold for the Quadritown number system since 21 | 441and 21 | (9)(49), but 21 ∤ 9nor does 21 ∤ 49. Note, this argument could be modified for each of the examples identified in part c.

 


This page titled 7.E: Exercises is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Pamini Thangarajah.

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