A DETAILED LESSON PLAN IN
MATHEMATICS 7
I. Learning Competencies
The learner evaluates algebraic expressions for given values of the variables. [M7AL-IIc-4].
II. Objectives
At the end of the lesson, the students must be able to:
1. Evaluate algebraic expressions for given values of the variables;
2. Find appropriate values of the variables that will make a given algebraic
expression true; and
3. Solve real-life problems involving algebraic expressions.
III. Subject Matter
Topic:
Evaluating Algebraic Expressions
Reference: E-Math Elementary Algebra pp. 199 - 202, KhanAcademy and Quipper
Instructional Materials:Laptop, Projector, PowerPoint Presentation, Visual aids, Activity cards
IV. Instructional Procedure
Teacher’s Activity
Student’s Activity
A. Preliminary
1. Prayer
Class let’s all stand up.
Before we start, Fjord please lead the prayer
The student will lead the prayer.
Dear God … … … Amen
2. Greetings
Good Morning class!
Good Morning Teacher Ezekiel! It’s nice to see you!
It’s nice to see you too.
Please pick up the pieces of paper under your
chair and check your alignment.
You may now take your seats.
Let’s check your attendance say present if you’re here.
(picking up the pieces of paper under the chairs)
(sitting down)
Present!
B. Lesson Proper
1. Review
Class! What was our lesson yesterday?
Yes, Angelene!
Sir! The lesson yesterday was about Writing Algebraic
Expression.
Very Good!
What is an Algebraic Expression?
Yes, Uno!
Very Good!
Sir! An algebraic expression is a mathematical statement
that contains a combination of numbers, symbols,
variables and mathematical operators. It does not have an
equals sign.
I need 5 students to give me an example of
Algebraic Expression and write it on the board?
Very Good! All of that are examples of Algebraic
Expression.
1. 2x3 – 1
5
2. x
3.
4. 4 + 2x
√ y−3
5.
3x
7 y−4
2y
x2+4x−4
C. Motivation
Now, class I have here sets of maze puzzles. All you
need to do is to answer the following question and
always keep in mind the PEMDAS RULE. You only
Yes, Sir
Food Monkey Delivery Service.
The task you all need to do is help the delivery man to
deliver all the foods to the right houses by correctly
answer the given set of questions. You must deliver all
the foods in 5 minutes.
Very Good!
D. Introduction
Algebra is one of the most interesting and challenging
part of Mathematics. It is where other branches of
Mathematics is derived. Also, it provides written language
in which mathematical ideas are expressed that makes
things easier, and problems are simplified using notation
and numbers instead of verbal descriptions.
E. Discussion
Now, I will discuss to you how to evaluate algebraic
expression.
Do you have any idea about on how to evaluate
algebraic expressions?
Yes, Garrete
Very Good!
For example, we are to evaluate the algebraic expression
2x – y for x = 4 and y =2.
Evaluating an algebraic expression simply means that we
have to simplify or reduce the expression down to a single
numerical value. As we have discussed earlier, variables
can assume multiple values. Hence, in evaluating
algebraic expressions, we have to substitute numerical
values to the variables.
If that’s the case what will be the result? If we substitute
the values for x and y in the given algebraic expression.
Who wants to try?
Yes, Cenia!
2x – y = 2(4) – (2)
= 8–2
=6
Very Good! It’s seems like you all did your advance
reading about our lesson.
Open your E-book on p.199
(Opening their E-Books)
Who wants to give me the steps on how to evaluate
algebraic expressions?
Yes, Enzo!
(Raising their hands)
Steps in Evaluating Algebraic Expressions
Very Good! Another One.
Yes, Ruby!
Very Good!
1. Replacing the variable by the given number value
(Substitution)
2. Performing the indicated arithmetic, following the order
of operations. (PEMDAS RULE)
So, for example you are asked to evaluate 4x +3,
when x = 4
Who can evaluate this algebraic expression using the two
steps?
Yes, Antonio!
4x +3, where x = 4
Well done!
Solution:
4x +3 = 4(4) + 3
= 16 + 3
= 19
For the next example is
2x−3
y +2
, where x = 3/2 and y = 4
2x−3
y +2
, where x = 3/2 and y = 4
Yes Fred
Solution:
Excellent!
2x+3
2
y−2 =
( 32 )−3
4+2
3−3
=
6
0
=
6
= 0
Another example is in word problem;
The length of a rectangle is 5 less than twice its width.
Find the perimeter of the rectangle if its width is 10cm?
Class! Who can give me the steps in solving word
problems? This is just a recap of your elementary word
problem solving.
Yes, Pao!
Very Good Pao!
Steps in solving word problem
1. Identify what is asked
2. List what are given facts (Represent the unknown
quantities using variables.)
3. Create a working equation
4. Solve the Problem
Who can tell me what is asked on the given problem?
Yes, Ian!
Find the perimeter of the rectangle
Excellent!
Who can tell me what are given facts?
Yes, Chinee!
Length (l) is 5 less than twice the width or 2w - 5
Very Good! Always remember to translate English phrase
to mathematical phrase.
Next who can create the working equation?
Yes, Krisha
The working equation will be
P = 2l + 2w
P: Perimeter
l: Length
w: Width
Excellent!
Lastly, who can solve the problem?
Yes, Kim!
Very Good!
P = 2(2w – 5) + 2w
Substitute the given value; that is w = 10.
Solution:
P = 2[2(10) − 5] + 2(10)
P = 2(15) + 2(10)
P = 30 + 20
P = 50
Therefore, the perimeter of the rectangle is 50cm.
F. Generalization
Are there any more question?
Yes, Kenzie!
No, if the denominator becomes zero the answer will also
be undefined.
Sir, regarding example the third example what will happen
if the denominator becomes zero? Will it also be equal to
zero?
Thank your Sir!
Is it clear now?
Yes, Sir!
Who wants to summarize the today’s lesson?
Yes, Regie
Excellent!
G. Application
Sir, in evaluating algebraic expressions, we need to follow
the two steps and always never forget the PEMDAS Rule.
And the steps in solving word problems in order to
evaluate algebraic equation we need to translate English
Phrases to Mathematical Phrases.
From this time class, I want you to try and solve this set
of problems on the board. I will use your index card to
identify the students that will be answering on the board.
1.
2.
9x−y
x+ y
8p−3q
, where x=3∧ y=2
1.
9x−y
, where x=3∧ y=2
x+ y
, where p = 4 and q = - 1
p+3 q
3. (2x2 + 3y) – 2, where x = 4 and y = - 3
Let’s pick the students that will answer the questions.
The first student to answer is Ishi
Solution:
9x−y
9(3)−2
= 3+2
x+ y
= 27−2
5
25
= 5
=5
The next is Carl
8p−3q
2.
p+3q
, where p = 4 and q = -1
Solution:
Then Kiesha
Job well done! You all got the correct answer.
8(4)−3(−1)
8p−3q
=
p+3 q
4+3(1)
32+3
= 7
35
= 7
=5
3. (2x2 + 3y) – 2, where x = 4 and y = - 3
Solution:
(2x2 + 3y) – 2 = (2(4)2 + 3(-3)) – 2
= (2(16) – 9) – 2
= (32 – 9) – 2
= 23 -2
= 21
V. Evaluation
Find the value of the algebraic expression. (5 minutes)
1.
6t−u
1.
6t−u
, where t = -2 and u = 3
2t+u
, where t = -2 and u = 3
2t+u
Solution:
2. Maria is five more than thrice the age of her son. In two
years, how old will Maria be if her son is 10 years old
now?
6(−2)−(3)
6t−u
=
2t+u
2(−2)+(3)
= −12−3
−4+3
−15
=
−1
= 15
Steps
1. Identify what is asked
- The age of Maria in two years
2. List what are the given. (Represent the unknown
quantities using variables.)
- Let s be the age of the son. Since Maria’s age is five
more than thrice the age of her son, the age of
Maria is 3s + 5.
3. Create working equation.
(3s +5) +2
4. Solve the problem.
Solution:
Substitute the given value; that is, s = 10.
Maria′s age = (3s + 5) + 2
= [3(10) + 5] + 2
= (35) + 2
= 37
Therefore, Maria will be 37 years old in two years.
VI. Assignment
For your assignment please answer this worksheet and
write your solutions in a one whole intermediate paper.
Goodbye Class! If you have questions or clarifications my
consultation time is posted at the faculty room. Have a
great day and God Bless.
Goodbye Sir Ezekiel. Thank you for teaching us. See
you tomorrow God Bless you and take care.
Prepared by:
Ezekiel D. Lapitan, LPT.