Leyte Normal University College of Education Mathematics Unit Tacloban City
A Semi-Detailed Semi-Detailed Lesson Lesson in Mathematics Mathematics Grade 7
Lhinever T. Gilhang Student, BSED 3-6
I.
Cristobal A. Rabuya Jr., M. Ed Teacher, Strategies in Teaching Mathematics
Objectives With the use of interactive hypermedia, the Grade 7 students are expected to do the following with 90% proficiency: a. illustrates the union and intersection of sets and the difference of two sets. b. state the importance of the union and intersection of sets in real life.
II.
Content and Materials A. Topic: Union Union and Intersec Intersection tion of Sets Sets B. Materials: 1. PowerPoint Presentation C. References: 1. DEPED. K to 12 Mathematics Curriculum Guide. DepEd DepEd Complex, Meralco Avenue, Pasig City, Philippines, page 80, 2013 M7NS-Ia-2 2. Mathematics – Grade 7 Learner’s Module. Book Media Press. Inc., 21- E Boni Seranno Ave., Quezon City, City, page 70, 2013. D. Method of Teaching: 4A’s
III.
Procedure
1. Activity The discussion will start by introducing the terms used in the topic through a game called 4 Pics 1 Word . The teacher will interact with the students by engaging them in the use of technology. The students will identify what word is being described by the pictures presented in the game.
2. Analysis The teacher will ask the following questions with regards to the activity: Guide Questions: 1. Are you familiar with the words associated in the game? 2. In your own words, what is a set? 3. In your own words, what is union? 4. In your own words, what is intersection?
3. Abstraction The teacher will show the students a problem. Mrs. Decosta, a Mathematics teacher wants to know who among her students can do arithmetic and who among her students can solve complex problems.
Set A Students who can do Arithmetic Marjorie Lovely Jeff Jonel Jake Milbert Roxette John Mark Mickee
Set B Students who can solve complex problems Jeff Jonel Jake Milbert John Mark
Students who can do arithmetic or can solve complex problems are Marjorie, Lovely, Jeff, Jonel, Jake, Milbert, Roxette, John Mark, and Mickee. Students who can do arithmetic and can solve complex problems are Jeff, Jonel, Jake, Milbert, and John Mark. The teacher will ask the following questions: 1. What can you observe in the table? 2. What does the statement “Students who can do arithmetic or can solve complex problems” implies? 3. What does the statement “Students who can do arithmetic and can solve complex problems” implies? The teacher will start discussing the union and intersection of sets by defining each term. Two sets can be added together. The union of A and B, denoted by A B, is the set of all things that are members of either A or B. For example: {1, 2, 3} {3, 4, 5} = {1, 2, 3, 4, 5} The teacher will go back to the problem given earlier and will ask the students the union of students who can do arithmetic and the students who can solve complex problems. A new set can also be constructed by determining which members of two sets have “in common”. The intersection of set A an d B, denoted by A B, is the set of all things that are members of both A and B. If A B = , then A and B are said to be disjoint. For example: {1, 2, 3} {3, 4, 5} = {3} The teacher will go back to the problem given earlier and will ask the students the intersection of students who can do arithmetic and the students who can solve complex problems. The teacher will present a problem and solve it interactively with the students.
There are 500 students in a school, 200 like science subject, 180 like math and 40 like both science and math. How many students like Science only? How many like Math only? How many like Math or Science? Let S= students who like science (200) M= students who like math (180) P1= students who like math only P2= students who like math and science P3= students who like science only
Solution: n(P1)
= n(M)-P2
= 180-40 n(P1) = 140 n(P3) = n(S)-n(P2) =200-40 n(P3) =160 n(M U S)= n(P1)+ n(P2) + n(P3) =140 + 40 +160 n(M U S)= 340
Therefore, 160 students like science only 140 students like math only 340 students like science or math.
4. Application The teacher will let the students answer questions through an interactive media. The teacher will call the students in random and answer the question by manipulating the laptop or simply clicking the correct answer. 1. {1, 3, 5, 7, 9} a. b. c. d.
{1,
2, 3, 4, 5}
{1, 2, 3, 4, 5, 6, 7, 9} {1, 3, 5} {1, 2, 3, 4, 5, 7, 9} {}
2. {7, 11, 13}
{13,
17, 19}
a. {13} b. c. {7, 11, 13, 17, 19} d. {7, 11, 17, 19} 3. {1, 2, 3}
{5,
10, 15}
a. {1, 2, 3, 5, 10, 15} b. {1, 2, 3} c. {5, 10, 15} d. 4. {1, 2, 3, 4, 5}
{2,
4, 6, 8, 10}
a. {1, 2, 3, 4, 5, 6, 8, 10} b. {1, 2, 3, 4, 5} c. {2, 4}
d. {2, 4, 6} After the interactive media presentation, the teacher will divide the class into five groups. The teacher will provide the same problem for the class and will answer it by group. In a school, there are 20 teachers who teach Mathematics or Physics. Of these, 12 teach mathematics and 4 teach both physics and mathematics. How many teach physics?
IV.
Evaluation
Do the following exercises. Write your answers on the spaces provided:
A = {0, 1, 2, 3, 4} B = {0, 2, 4, 6, 8} C = {1, 3, 5, 7, 9}
Test I. Given the sets above, determine the elements and cardinality of:
a. A U B = {0, 1, 2, 3, 4, 6, 8} ; n (A U B) = 7 b. A U C = {0, 1, 2, 3, 4, 5, 7, 9} ; n (A U C) = 8 c. A U B U C = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} ; n (A U B U C) = 10 B = {0, 2, 4}; n (A
d. A
e. B
C
f. A g. (A
= Ø; n (B
B B)
B) = 3
C) = 0
C = Ø; n (A
B
C) = 0
U C = {0, 1, 2, 3, 4, 5, 7, 9} ; n ((A
B) U C) = 8
Test II. Solve the problem and show necessary solution.
1. A group of 25 high school students was asked whether they use either Facebook or Twitter or both. Fifteen of these students use Facebook, and twelve use Twitter.
a. How many use Facebook only? b. How many use Twitter only? c. How many use both social networking sites?
Test III. Write a brief essay about the importance of union and intersection of sets in everyday life.
V.
Assignment Read in advance about the absolute value of a number on a number line. Reference: 21-
Mathematics – Grade 7 Learner’s Module . Book Media Press. Inc., E Boni Seranno Ave., Quezon City, page 76, 2013.
