Grade 7 Mathematics
Mathematics 7 Learning Materials
Saturday, May 13, 2023
Monday, September 28, 2020
SETS
The set is a well-defined group of objects called elements that have something in common or follow a certain rule. Set notation uses braces { } with elements separated by commas. The braces indicate that the objects written between them belong to the set.
Union of sets. The union of two sets is the set of all elements that belong to both A or B. It is denoted by AUB and is read as “union of A and B”
Intersection of Sets. The intersection of two sets is the set of all elements that are common to both sets. It is denoted by A∩B and is read as “A intersection B”
1. Describe Set A
2. Describe Set B
3. What is AUB?
4. What is A∩B?
The complement of a set A', is the set of all elements found in the universal set U, that are not found in set A.
Therefore, there are 16 subsets.
Activity 1
Can you group, name and list the following objects?
1. How many sets are there? ANSWER
2. Can you name each set? ANSWER
3. Name the elements of each group. ANSWERLearning Task 1:
Identify all the possible answers for the statements below.
1. Colors of the rainbow
Set C = { red, orange, yellow, green, blue, indigo, violet }
2. Letters used in the word "Mathematics"
Set M = { m,a,t,h,e,i,c,s }
3. Grade 7 sections of Santiago NHS
Set S = { Aquino, Bonifacio, Jacinto, Laurel, Ponce }
UNION AND INTERSECTION
Union of sets. The union of two sets is the set of all elements that belong to both A or B. It is denoted by AUB and is read as “union of A and B”
Intersection of Sets. The intersection of two sets is the set of all elements that are common to both sets. It is denoted by A∩B and is read as “A intersection B”
Activity 1
2. Describe Set B
3. What is AUB?
4. What is A∩B?
Can you identify the elements in each set?
4. What are the elements of B only?
COMPLEMENT OF A SET
The complement of a set A', is the set of all elements found in the universal set U, that are not found in set A.
The universal
set U is the set that contains all objects under consideration.
From the given example, the universal set is
U = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }
The complement of set A is
A' = { 4, 7, 6, 3 }
From the universal set, we can also get subsets.
Subsets are elements of A that are also elements of the universal set U.Example
U = { 1, 2, 3, 4 }
The subsets are:
{ 1 } { 2 } { 3 } { 4 }
{ 1, 2 } { 1, 3 } { 1, 4 } { 2, 3 } { 2, 4 } { 3, 4 }
{ 1, 2, 3 } { 1, 2, 4 } { 2, 3, 4 } { 1, 3, 4 }
{ 1, 2, 3, 4 } { }
{ } This is called a NULL set. Null set is an empty set. It is a subset of all set.
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