MATHEMATICAL SYSTEM

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Course Title:MATHEMATICS IN THE MODERN WORLD

MODULE 3
MATHEMATICAL SYSTEM
Module Introduction
Historically, a mathematical system consists of undefined terms, definitions, postulates or
axioms, propositions or theorems as contained on the classic Book I of the Elements written by a
Greek mathematician, Euclid of Alexandria. This treatise systematizes Geometry containing 23
definitions, 5 postulates, 5 common notions, and 48 propositions (Baltazar, Ragasa, &
Evangelista, 2018).
Notably, these geometric concepts were already
introduced and applied by the Egyptians and
Babylonians who came before Euclid. The Elements
of Euclid philosophizes these concepts putting them
into more coherent, abstract and consistent ideas. It
establishes “geometry as a primary inquiry” (Young
Ocean, 2019).
Nothing has changed about the system that Euclid
has in his geometry up to the present day. All of his
propositions can be reproduced by a contemporary
student with accuracy equivocal to how Euclid
demonstrated it. Geometry has become a concrete
mathematical system where the elements of a set are
concreted or illustrated into concrete figures, and on
how these objects of the set are related.
However, in this Module, the learners will learn that a mathematical system is also an abstract or
algebraic system with the concept of set as building block. The emphasis on this section is the
study of the important properties of a mathematical system of a set of integers, the remainder
function particularly modular arithmetic.

LESSON NO.1
LESSON TITLEBINARY OPERATIONS
Specific Learning
Outcomes:
During the learning engagements, the learners should be able to:
1. Discuss the nature and properties of a mathematical system through
some forms of semantic maps;
2. Determine the binary properties satisfied of a given mathematical
system; and
3. Explain your stand on the adage: “Mathematics, as building block of
technology, revolutionizes society.”
TEACHING LEARNING ACTIVITIES
PROCESSING
1. Defining a Mathematical System. Investigate which among the three ordinary operations
in real number is/are binary – addition, multiplication, division. The following are the
instructions: Perform the following indicated operations on a set of real number , if it exists.
a. 1 + 5 (defined, solution exists) f. 6 ÷3(defined, solution exists)
b. 7 · 0 (defined, solution exists) h. 0 ÷ 4 (defined, solution exists)
c. 3 · 6 (defined, solution exists) i. 0 · 0 (defined, solution exists)
d. 0 + 8 (defined, solution exists) j. 4 ÷ 0 (undefined, solution does not exist)
e. 5 · 8 (defined, solution exists) h. 0 ÷ 0 (indeterminate, solution does not exist)

Euclid of Alexandria and his Book Elements. Photo retrieved
from https://miro.medium.com/max/500/1*4ijBUB_OSisa7Y2
Fmrihw.jpeg
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Considering the entire set , Only Addition and Multiplication are defined to all elements of
? (Hence, BINARY OPERATIONS)
DEFINITION:
A Mathematical System is a set with one or more binary operations defined on it, and
a binary operation is a rule that assigns to 2 elements of a set having a unique third element.
PROPERTIES OF BINARY OPERATIONS/BINARY PROPERTIES
 CLOSURE OF A SET (Special Property of Binary Operation)
“A set is said to be closed under binary operation * if for any two members from the set, the
result of the binary operation returns a member of the set.”
Example: for all elements under the given SET OF INTEGERS (Z),
If 5+2=7, then this equation is closed.
If 5*2=10, then this equation is also closed.
(1) Note that 5 and 2 are members of the set of all integer numbers
(2) Performing any binary operation to 5 and 2 will produce 7 (if
addition) and 10 (if multiplication)… and 7&10 are both integers as well
(3) Going back to the definition of CLOSURE, (5+2=7) and (5*2=10)
are closed because the 2 members of the integer set (5 and 2) produced
another members of the given set of integers (7 and 10)
Determine if the operations and equations below are closed or not:
There’s a given set X.
X=1, 2, 3, 4, …100
Is (25 and 75) closed under the binary operation?
Check!
By addition: 25+75=100 (25,75, and the third element 100
are all members of the set X.
Hence, CLOSED under addition)
By Multiplication: 25*75= 1875 (25 & 75, are all members of the
set X. However, 1875 does
not belong to set X. Hence,
NOT CLOSED under
multiplication)
For the remaining 4 basic binary properties…
Suppose we consider a finite set S = 1, 2, 3, 4 and a binary operation , and let the
operation  be defined on the following table.
1 2 3 41 2 1 4 32 1 2 3 43 4 3 2 14 3 4 1 2
We could see that the mapping of 1 onto 3 is 4, or simply written as 13 = 4. Similarly, 23 =
3. We note that, the operation  is closed in S because said operation is defined in all elements
of S.

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 COMMUTATIVITY
“A Binary operation * defined on a set R of real numbers is COMMUTATIVE if
a*b=b*a, for all a, b are elements of R”
We can also verify that
13 = 4 and
31 = 4.
Also, 24 = 4 and
42 = 4.
This shows that the operation  is commutative…
We can verify this furthermore because there is a symmetry that exists with respect to the
diagonal.
1 2 3 41 2 1 4 32 1 2 3 43 4 3 2 14 3 4 1 2
 ASSOCIATIVITY
“A Closed Binary operation * defined on a set R of real numbers is ASSOCIATIVE if
a*(b*c)=(a*b)*c, for all a, b, c are elements of R”
We also verify whether 1(23) = (12)3 or not.
We take the innermost operation first, as it was introduced to you in elementary and high
school.
1(23) = (12)3
13 = 1 3
4 = 4.
Another…
3(14) = (31)4
33 = 44
2=2
 EXISTENCE OF IDENTITY
“An identity element of a binary operation is a single element that will return to its original
value when the operation is performed.”
The identity element of the binary operation * on a set S is w
for which a * w = a, for all a, w are elements of S.

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Notice that,
1  2 = 1 3  2 = 3
2  2 = 2 4  2 = 4.
Thus, 2 is the identity element of the binary operation .
 EXISTENCE OF INVERSE
“The inverse of the binary operation * on a set S is e
for which a * e = w, where w is the identity element of * on S,
and where all a, e, w are elements of S”
We can also decipher from the given operation that: (note that we have previously seen that 2
is the identity element of the binary operation  on set S)
1  1 = 2 3  3 = 2
2  2 = 2 4  4 = 2.
We can say that the inverse of 1, written as 1-1, is 1; the inverse of 2 is 2 or 2-1 = 2. Similarly,
3-1 = 3 and 4-1 = 4.
FORMATION ACTIVITY
Answer the attached Activity on the Anticipation Guide for Binary Operation, titled as Binary
Operations – “Do Now” retrieved from https://www.easyteacherworksheets.com/math/algebra
binaryoperations.html.
2. Based from their answers on the Activity, ask the following:
2.1. How important is the concept of set in understanding a
mathematical system?
2.2. Why are the properties of binary operation important in
understanding the nature of a given mathematical system?
2.3. A certain mathematical system may be designed in order to
solve certain issue of humanity. What is your stand on the
adage: Mathematics, as building block of technology,
revolutionizes society? Explain further your answer.
SYNTHESIS ACTIVITY
1. Design any semantic map or diagram that would show the relationship of the following
terms. Give a brief description of your map.
binary operation set mathematical system closure property
Commutativity associativity identity inverse
2. Complete the given KWL Chart to show what you know, what you wonder and what you
have learned from this lesson.
What I KNOW about this lesson? What I WONDER about this lesson? What do I LEARNED from this lesson?

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ASSESSMENT1. Suppose we consider a finite set X = N, I, K, O and a
binary operation ®, and let the operation ® be defined on the
following table:
®N I K ON K N I OI N K O IK I O K NO O I N K
Determine if the binary operation ® exists and is defined in the
given set X by verifying all the Binary Properties:
 CLOSURE
 COMMUTATIVITY
 ASSOCIATIVITY
 EXISTENCE of IDENTITY
 EXISTENCE of INVERSE
2. Why the ordinary division (÷) is not a binary operation in the
set of real number?
3. Let the operation © be defined on a set of integer Z,
such that
a © b = 2a – b, for all a, b Z
Find the value of
3 © (-1) = ________
Hint: substitution of values for a and b…

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4. In relation to number 3, is operation © closed or not? Please
justify
5. 
0 1 2 30 0 1 2 31 1 2 3 02 2 3 0 13 3 0 1 2
5.1. Is  closed? Justify.
5.2. Show that  is commutative
5.3. Does Associativity in  exist? Justify.
5.4. What is the identity element of the operation ?
5.5. What is/are the inverse element(s) of the operation
?
REFLECTIVE LEARNING
6. Cite a certain mathematical system applied to the program or
course that you are taking. Describe how mathematical systems
work and benefit the humanity.

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RESOURCES:Baltazar, Ragasa, & Evangelista, Justina(2018). Mathematics in
the Modern World. C and E Publishing Inc.
https://study.com/academy/practice/quiz-worksheet-binary
operation-binary-structure.html.
https://www.youtube.com/watch?v=A5bMGt8inM0&list=PL9bj
pkdabbOsz314XDGNiS2s7o3ZDQPUJ&index=5
https://www.youtube.com/watch?v=jKoMerdR2Ig.
https://www.easyteacherworksheets.com/math/algebra
binaryoperations.html.
Young Ocean (2019). Math and Magic: Euclid Defines Space.
Retrieved on 5 July 2020 from
https://medium.com/@sunfaceman/math-and-magic
euclid-defines-space-ea987f61709c.