b.ed discussion lesson plan algebric equations by amit kumar sldav ambala

1. Discussion Lesson Plan
(Mathematics)
Class VIII
Topic
Algebraic Expressions and Identities
TIME DURATION 30-35 MINUTES

2. Presented By :-
AMIT KUMAR
ROLL NO 36
SOHAN LAL DAV B.ED COLLEGE

3. 1. Objectives:-
Knowledge:-
The students will be able to know the identities in algebraic
expression and will be able to represent it geometrically.
Understanding:-
The student will be able to know the relationship between
algebra, geometry and arithmetic's.
The students will also be able to understand the relationship
between the algebraic expressions.
Application:-
The students will be able to generalise the algebraic expressions
from the exercises based on pictures and numerical.
Skill:-
The students will be able to use algebraic expressions in daily life .

4. 2. Instructional aids to be used
1) General Teaching Aids – Pointer, chalk ,
duster, black board
2) Specific Teaching Aids - Power point
presentation on Algebraic expressions and
identities

5. 3. Material Required for activity:-
Pencil, geometry box, notebook, pen
glaze paper, scissors, pasting material
etc.

6. 4. Previous Knowledge:-
Children have studied mathematics up to
class 7th and they are aware about
variables, constants and algebraic
expressions.

7. P.K TESTING

8. • Before we start I want to ask you one
Interesting question. Have you ever learnt
algebra, when you were very small kid?
• Your Simple flat answer is NO.

9. • But I say yes, you have learnt algebra when you were a small
baby and your mother started calling you chikki, duggu. Do
you know from where these names came?
Duggu! Where r
u?

10. • Since you were unnamed that time and your
mother wanted to interact with you, she
needed some variable to address you and she
started calling you by these names. You learnt
that it was your name and started giving
response to mother with smile.

11. Similarly in mathematics when we
represent numbers 2, 3, 4 with some
other names like a, b, c these are
called variables. Variables and
constants form a term and terms are
added to form algebraic
expressions.
Your name is a variable which
you learnt when you were kid.

12. Announcement of the topic-
Hi Students!
Today in this class of mathematics we
are going to study about use
Identities in algebraic expressions .

13. 6. Content:-
• Let us see how we can represent different
numbers and algebraic expressions
geometrically.

14. This is what we call
geometrical expression of
algebraic expression. When
we use variables to represent
certain values we deal with
algebra.

15. So I must assume that you know algebra.
Let us perform one activity:
But before that one more question for you
Why 4, 9, and 16 are called squared numbers?

16. Because we represent them with squares

17. We can also represent squared algebraic terms
with squares.
X2 is the area of a square with side length X.
Area of a square of side X = X2
And area of a square of side (a + b)= (a + b)2

18. a2 + ab + ab +b2 = a2 + 2ab + b2
(a + b)2 = a2 + 2ab + b2
ACTIVITY-1

19. Did U know? You can apply the algebraic identity to
work out arithmetic problems
IDENTITY TAKEN:-
(a + b)2 = a2 + 2ab + b2
Example: (17)2 = (10 + 7 )2
= 102 + 2(10) (7) + 72
= 100 + 140 + 49
= 289

20. (a – b)2 + ab + (a – b)b = (a – b)2 + ab + ab – b2
a2 = (a – b)2 +2 ab – b2
=> (a - b)2 = a2 - 2ab + b2
ACTIVITY-2

21. You can also apply the algebraic identity to work
out arithmetic problems
IDENTITY TAKEN:-
(a - b)2 = a2 - 2ab + b2
Example: (17)2 = (20 - 3 )2
= 202 - 2(20) (3) + 32
= 400 - 120 + 9
= 289

22. (a + b) (a-b) = a(a-b)+b(a-b)
= a2-ab+ba-b2
(a + b) (a –b) = a2 – b2
ACTIVITY -3

23. You can also apply the algebraic identity to work out arithmetic
problems
IDENTITY TAKEN:-
(a + b) (a –b) = a2 – b2
Example: (17 X 23) = (20 - 3) (20 +3)
= 202 - 32
= 400 – 9
= 391

24. What is an identity?
Consider the equality, (a+1)(a+2)=a2 +3a+2
For a=2
We can show LHS=RHS,
(2+1)(2+2)=22 + 3(2)+2
12=12
Let us now take a=-3
Then also,
(-3+1)(-3+2)=(-3)2+3(-3)+2
2=2
Such an equality, true for every value of variable in it, is called
IDENTITY

25. 7. What have we learnt?
An identity is equality, which is true for all values of
the variables in the equality.
The following are the standard identities:
(a + b)2 = a2 + 2ab + b2 -------------------------(1)
(a - b)2 = a2 - 2ab + b2 -------------------------(11)
(a + b) (a –b) = a2 – b2 --------------------- (111)
The above identities are useful in carrying out squares
and products of algebraic expressions. They also allow
easy alternative methods to calculate products of
numbers

26. 8. Now try these questions:-
1) Using the identity (1) find
(i) (2x + 3y)2
(ii) 1032
2) Using the identity (11) find
(i) (4p - 3q)2
(ii) (4.9)2
3) Using the identity (111) find
(i) (3/2 m + 2/3 n) (3/2 m – 2/3 n)
(ii) 9832 - 172
(iii) 194 X 206

27. 9. Try at Home:-
1. Represent the identity (a + b)2 = a2 + 2ab +
b2 by taking the value of a =3 and b = 4
geometrically.
2. Using identity find the value of the
arithmetic problem (104)2.
3. Find the product of 104 X 96 by using the
algebraic identity.

28. Thank you
