1. LESSON PLAN NO.23
CONTENT ANALYSIS:-
New Term : Approximate value
Fact : Approximate values of all irrational numbers can be find out
Concept : Concept of approximate values of irrational numbers
Process : Process of finding the approximate values of irrational numbers
LEARNING OUTCOMES
The pupils will be able to
1. recall the term irrational numbers.
2. explain the term irrational numbers
3. identify the concept of approximate value
4. give illustration for approximate value
5. through familiar examples of irrational numbers an unfamiliar situation is made
clear
6. suggest a different method to find the approximate values of irrational numbers
7. discuss the problem of irrational numbers with other students
8. ask questions to know more about irrational numbers
9. visualize the mathematical relationship of irrational numbers in daily life situation
NAME OF THE TEACHER: PRIYA LEKSHMI S
SUBJECT : MATHEMATICS
UNIT : IRRATIONAL
NUMBERS
SUB UNIT : APPROXIMATE
VALUES OF
IRRATIONAL NUMBERS
NAME OF THE SCHOOL :GURUDEVA
HIGH SCHOOL
STANDARD : IX B
STRENGTH :28/33
DATE : 19.08.2015
TIME : 40 Min.
CURRICULAR STATEMENT: To understand about irrational numbers, approximate
Values and its importance in Mathematics through
observation, organization of charts and by analyzing the
prepared notes of the pupil.
2. 10.recognize the qualities of exactness and accuracy while doing problem on
irrational numbers
11.read charts quickly and accurately on irrational numbers
PRE REQUISITES – The students have knowledge on rational and irrational numbers
TEACHING LEARNING RESOURCES – Usual classroom aids, chart
LEARNING STRATAGIES – Individual work, observation, activity and explanation
by the teacher
Classroom interaction procedure Expected pupil responses
INTRODUCTION
ACTIVITY -1
i. What is irrationals ?
ii. Is square of any number is 2?
Through these questions the teacher leads
the students to the topic
PRESENTATION
ACTIVITY – 2
Teacher says that the square of any rational
number is not 2. But we can construct a
sequence of rational numbers, whose
squares are closer and closer to 2.
Teacher draws a line.
0 1
If we divide the line in to 10 equal parts,
what are the fractions we get?
Teacher draws another line on black board
All the pupil answered correctly.
Pupil says no.
Pupil answered 1/10, 2/10,3/10…
3. 1 2
If we divide the above line into 10 equal
parts, what are the fractions we get?
Right, these numbers also can be written as
1.1, 1.2, 1.3…
Teacher asks to find the square of above
numbers.
1.21, 1.44, 1.69, 2.25…
[B.B]
Teacher asks the students to find the difference
between 2and the square of 1.4
2-(1.4)²=.04
[B.B]
Can we make the difference smaller?
ACTIVITY-3
Teacher asks the students to divide the interval
between 1.4and1.5 into 10 equal parts
1.41,1.42,1.43,…,1.49
[B.B]
Then she asks to find the squares
1.41²=1.9881
1.42²=2.0164
[B.B]
Teacher explains
2-(1.41)²=0.0119
Finding like this, we get
2-(1.414)² = 0.000604
2-(1.4142)² = 0.00003836 and so on
The square of the rational numbers
1.4, 1.41, 1.414, 1.4142…are very closer to 2
Therefore we can write
√ =1.4142
This rational number is called approximate
value of √
ACTIVITY-4
Teacher show the chart containing the
Pupil answers 1 1/10, 1 2/10,….
Pupil find the squares and read.
Pupil says 0.04
Pupils feel difficult
Pupils find the answer.
Pupil finds.
4. approximate values
SL.NO. IRRATIONAL
NUMBER
APPROXIMATE
VALUES
1 √ 1.414
2 √ 1.732
3 √ 2.236
4 √ 2.449
5 √ 2.646
ACTIVITY-5
Teacher asks the students to find the perimeter
of the triangle shown below.
2 cm
3cm
Hypotenuse= √ =√ cm
Therefore, Perimeter =2+3+√
=5+√
Since,√ =3.6055
Perimeter=5+3.6055
=8.6055
≈8.6cm
The symbol ≈ means approximately equal to.
CLOSURE
ACTIVITY-6
Teacher concludes the class by saying
about approximate value.
5. REVIEW
ACTIVITY-7
Teacher asks the questions about learned
portion
FOLLOWUP ACTIVITIES
i) Find the approximate value of √ ?
ii) Find the approximate value of √ ?
Pupil answered correctly.
