Republic of the Philippines
Department of Education
Division of Eastern Samar
CAN- AVID NATIONAL HIGH SCHOOL
Can- avid, 6806
LESSON PLAN IN MATHEMATICS 7
Date: ____________
Time: ____________
Grade and Section: 7- Anthurium, 7- Bluebell, 7- Jasmin
Learning Competency 1: Describes well-defined sets, subsets, universal sets, and the null set and
cardinality of sets (M7NS-Ia-1)
I.OBJECTIVES
a. Describe well-defined sets, and null set
b. Identify the elements, subsets and cardinality of a set.
c. Appreciate the importance of sets
II.SUBJECT MATTER
Topic: Sets: An Introduction
Subtopic: Terms Related to Sets
Materials: LCD, Pictures, activity sheets
References: Learners Material for Grade 7 pages1-3, Patterns and Practicalities on
G7- Math pages: 5-10 Gladys Nieverra
III.PROCEDURE
A. Preliminaries
Motivation
Below are some famous characters and places. Which do you think does
NOT belong in each group? Why?
Bunga View Deck
Avidturer
GPark
Burp
The East Wing
B. Lesson Proper
1. Teaching/ Modeling
Look at the objects below
a. Which objects belong together?
b. How many numbers/elements are there in each set?
c. Is there an object that belongs to more than one
group? Which one?






A set is a collection of objects ,things or symbols which are clearly defined .In the objects
above the sets are;
1. Set of school supplies
3. Set of things worn by girls
2. Set of gadgets
4. Set of things worn by boys
The groups are called sets for as long as the objects in the group share a characteristics
and are thus, well defined. We have four well-defined sets in the objects above.
The individual objects in a set are called the members or elements of the set. Example: three of
the elements in set 1 belong to a set of school supplies ( ruler, ballpen, and notebook ). Can you
name elements of other sets?
The symbol “ ∈ ” is used to indicate that an object is an element or member of the set.
When we define a set, if we take pieces of that set, we can form what is called a subset. For
example, we have the set { 1,2,3,4,5}.
A subset of this is { 1,2,3,},another subsets are { 3,4}, {2,3,5} or even { 1 }. However,
{1,6} is not a subset, since 6 is not in the parent set.
A symbol for subset is ⊆.
 The universal set U is the set that contains all objects under consideration. At
the start, “objects” is our universal set
 The null set is an empty set. Example: If H is the set of boys in a exclusive school for girls,
then H is called empty set since there were no boys in that school. The null set is a subset
of any set. The symbol ∅ or { } will be used to refer to an empty set or null set.
 The cardinality of a set is the number of elements contained in that set. Example: In the
objects given, the cardinality of set of gadgets is 3, set of things worn by boys is 2. The
cardinality of a set A is written as n(A).
2. Analysis
a. Did you group the objects correctly?
b. How many sets elements are there in each set?
c. Can you give your own examples of well-defined sets and null set?
d. What is the importance of sets in daily life?
3. Guided Practice
Do what is asked:
a. Is the given set well-defined? Justify your answer.
1. { subjects in Grade 7 } Yes/No because _
2. { popular actors
}
Yes/No because_
b .Which of the following are empty sets and why?
1. Triangles with four sides. It is an empty set because
2. Pandas in the Philippines .It is an empty set because
3. Actors who are politicians. It is a set because
c. Identify the elements, subsets and cardinality of the given set
C= { first five counting number}
Elements: 1, 2, 3, , Subsets: {1}, { 1,2},{ },{ } Cardinality: n( C)=__
4. Independent Practice
Complete the table by determining whether the given set is well-defined, not well-defined or
null set. If well-defined, give the elements, three subsets and its cardinality.
SETS
DESCRIPTION
ELEMENTS
(∈)
SUBSETS
⊆
CARDINALITY
(n)
1. A= {school days}
2. B= { baldmen with
braided hair}
3. C= {whole numbers less
than 5}
4. D= {vowels in the
alphabet}
5. E= {pretty girls}
5.Generalization
Terms to Remember
1. A set is a well- defined group of objects,
called elements that share a common
characteristic
Notations and Symbols
1. Uppercase letters will be used to name sets
and lowercase letters will be used to refer to
any element of a set. For example, let M be the
set of all objects on activity. We write,
M={ballpen,notebook,crayon and ruler}
The symbol “ ∈ ” is used to indicate that an
object is an element or member of the set
2. When a set is contained in another set B,
we say that set A is a subset of set B
2 if .A is a subset of (or is included in) B,
then we write
,
3. The universal set is the set that contains all
objects under consideration
3. Universal set is denoted by U.
4. The null set is an empty set. The null
set is a subset of any set.
4. The symbol ∅ or { } will be used to refer to
an empty set or null set.
5. The cardinality of a set A is the number of
elements contained in A.
5. The cardinality of a set A is written as n(A)
6. Application
THINK-PAIR-SHARE: Do the following exercises
1. Give 3 examples of well-defined sets and null sets
2. Name 3 elements in each of the given sets
a. {Municipalities in Eastern Samar}
b. {Cellphone brands}
3. Let B= { a,i,m }.List all the possible subsets of B.
7. Assessment
If K={ counting numbers from 1-10}, L={consonants in word art }, and
M= { whole numbers between 9 and 10};
A. Which of the sets are well-defined? null set?
B. Find;
1.elements of K
2.elements of M
3. subsets of M
4. three subsets of L
5. cardinalities of all the sets
IV.ASSIGNMENT
1. Consider the sets:
A= {1, 3, 5,}
D= the odd numbers less than 7
B= {2,4,6, }
E= the whole numbers less than 7
C= {0,1,2,3,4,……}
Answer the following;
a. Name the elements of set A
_b Name.the elements of set C
_c. Is set D a subset of set C? Why?
_d. Is set C a subset of set D? Why?
_e. Which of the sets are subsets of set C?
2. Study union and Intersection of sets.
Prepared by:
GRETCHEN VANESSA G. GENISTON
Subject Teacher
Checked by:
MITOS C. NOROMABA
MT-I/ DEPT. HEAD
Answer Key:
Preliminary Activity
a.1.ballpen,notebook,ruler
2.cellphone, laptop ,video camera
3. objects worn by girls
4. objects worn by boys
b. There are 4 sets/ groups
Guided Practice
A. 1. Yes, because subjects in Grade 7 are well defined.
2. No, because some people may consider an actor popular while others do not.
B. 1. Triangles with four sides. It is an empty set because triangle has three sides
2.Pandas in the Philippines. It is an empty set because there is no Panda in the
Philippines
3.Actors who are politicians. It is a set because there are actors who are also
politicians.
C .Elements: 1,2,3, 4, 5
Subsets: {1},{1,2}{1,2,3,},{3,4,5,}……
Cardinality: n (C))= 5
Independent Practice
Set
1.A={schooldays }
Descript
ion
Welldefined
2.B={ baldmen with
braided hair}
Null set
3.C={wholenumbers
less than five }
Welldefined
4.D={vowels of
alphabet }
5.E={ pretty girls}
Welldefined
Not welldefined
Elements
( ∈)
Subset⊆
Monday,Tuesday
Wednesday,
Thursday,Friday
{Mon,Tues}
{Tues.Wed}
{Wed.,Fri}..
none
{0}
{1},{1,2},{2,3,}
,{2,3,5},{4,5}
{ }………
0,1,2,3,4
a,e,i,o,u
{a }{e},{a,e }
{I,o,u }…….
Application
1. Answers may vary
2. a. {Naic, Ternate, Maragondon, Tanza, Silang……….}
b. {Samsung, Nokia, Iphone, Cherry Mobile……}
3. { },{a },{i}, {m }, {a,i} {I,m},{a,m},
Assesment
A. Sets K and L are well-defined ,while Set M is a null set
B. 1. { 1,2,3,4,5,6,7,8,9,10}
4. { } { r }, { t}, { r,t }
2. none
5. n( K )= 10, n (L)= 2
Cardinali
ty
5
5
5
3. none or { }
n(M)=0