14. REVIEW:
Write 4, 5, 6, 7, 8, 9, and 10
using
a. roster method
b. descriptive method
c. set-builder notation
15. describe sets and their subsets
the union of sets, and the
intersection of sets
Target Objective
16. MATH BANK
SETS - A group or collection of objects
ELEMENTS - Objects or members of the set.
Descriptive method - writing a description of
its elements
The Roster method - listing all its elements
within a pair of braces, {}.
Set-builder notation - using a variable.
17. Well-defined Sets
- element that is ”clearly defined” or ” clearly
described”
Set of Vowels in the English
Alphabet
Set of Even Numbers Less Than 10:
M = {Grade 7 Mathematics
Lessons}
Is the set of favorite fruits a well-defined
set?
Explain your answer.
19. Cardinals
- number of elements in the set.
B = {red, blue yellow}
Its cardinal number is 3.
It is written as n(B) = 3
It is read as “cardinality of set B is 3”.
C = {a, e, i, o, u}
n(C) = 5
20. Null Set
A set with no elements. {} or Ø
B = {xlx is a triangle with four
sides}
D = {students who ride a helicopter
every day}
G = {Set of months in a year with 32
days}
21. Finite Set
A set whose number of elements can be
counted
A = {-1, -2, -3, -4, -5}
B = {x l x is a multiple of 5 between 10
and 50}
C = {sets of letter in the Philippine
alphabet}
22. Infinite Set
A set whose number of elements CAN NOT be
counted
A = {-1, -2, -3, -4, -5,...}
B = {x l x is a multiple of 5}
C = {sets of name of a person}
24. describe sets and their subsets
the union of sets, and the
intersection of sets
Target Objective
25. EQUAL SETS
Two sets are equal if they have exactly the
same elements
A = {x l x is a multiple of 3 between 1 and 10}
A = {3, 6, 9}
B = {9, 3, 6}
A = B because both sets have the same elements.
H = {x l x is a letter in the word "SILENT"}
H = {S, I, L, E, N, T}
K = {N, T, E, L, S, I}
H = K because the letters in both sets are identical
26. EQUIVALENT
SETS
Two sets are equivalent if they have the
same number of elements
A = {1, 2, 3}
B = {a, b, c}
A B
∼ because both sets have 3 elements.
H = {circle, square}
K = {5, 10}
H K
∼ because both sets have 2 elements.
27. UNIVERSAL SET
It contains all elements considered in the
situation. It is denoted by U.
set of students in class
U = ALL students in the school
set of vowels in the alphabet
U = ALL letters in the alphabet
set of numbers in the 10 cards is
U = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
28. SUBSET
Set A is a subset of Set B if and only if every
element of A is also an element of B. It is
written as A⊆B
A = {1, 2, 3}
B = {1, 2, 3, 4, 5}
A B
⊆ because all
elements of A are in the
set B
A = {j, n, r}
B = {j, e, n, y}
A B
⊆ because r is not an
element of B
29. PROPER SUBSET
Set A is a proper subset of Set B if and only if
every element of A is also an element of B
and B contains at least one element not in
A. It is written as A⊂B
A = {j, n}
B = {j, e, n, y}
A B
⊆ because all
elements of A are in the
set B
