NCERT Solutions Class 7 Maths Chapter 4 Expressions Using Letter-Numbers Exercise 4.2

Exercise 4.2 of Class 7 Maths Chapter 4: Expressions Using Letter-Numbers deals with solving equations with algebra. In this exercise, the students will understand how to determine the value of a variable when the equation is presented. These are simple one or two-step problems that provide essential introductory learning in algebra. 

The questions are written so students understand that letters like x or y can be used instead of numbers and how to work back to determine their value. This is a very important topic for exams, as it gives an introduction to the foundation of algebra covered in greater depth in higher classes. 

There are solutions provided in accordance with the latest CBSE prescribed guidelines and the updated NCERT syllabus. To enhance your learning, we have provided step-by-step NCERT Solutions to resolve each question clearly. Our NCERT Solutions are free downloadable, and designed to assist you in not only scoring better in your exams, but to also understand algebra easier.

1.0Download NCERT Solutions Class 7 Maths Chapter 4 Expressions Using Letter-Numbers Exercise 4.2: Free PDF

Exercise 4.2 helps the students to solve simple equations & find the unknowns. It lays the foundational basis for the study of algebra in higher years. Our NCERT Solutions of Class 7 Maths Chapter 4 offer step-by-step solutions to every question. Download the free PDF.

2.0Key Concepts in Exercise 4.2 of Class 7 Maths Chapter 4

Below are the key concepts covered in the exercise 4.2 of class 7 maths chapter 4

• Solving one-step equations involving addition or subtraction
• Solving one-step equations involving multiplication or division
• Finding the value of a variable using simple operations
• Understanding equality and balance in equations
• Applying logic to reverse the operations and isolate the variable

3.0NCERT Class 7 Maths Chapter 4: Other Exercises

4.0NCERT Class 7 Maths Chapter 4 Exercise 4.2: Detailed Solutions

1. Add the numbers in each picture below. Write their corresponding expression and simplify them. Try adding the numbers in each picture in a couple different ways and see that you get the same thing.

Sol.

Way-1 5y + 5y + x + x + (-6) + 2 = 10y + 2x - 4

Way-2 (2 * 5y) + (2 * x) + (-6 + 2) = 2(5y) + (2x) + (-4) = 10y + 2x - 4

Way-3 2(5y + x) + (-6 + 2) = 10y + 2x - 4

(2p) (3q) -2, 3

(3q) (2p) 3 - 2

(2p) (3q)

(3q) (2p)

Way-1 2p + 3q + (-2) + 3 + 3q + 2p + 3 + (-2) + 2p + 3q + 3q + 2p

= 2p + 2p + 2p + 2p + 3q + 3q + 3q + 3q + (-2) + (-2) + 3 + 3

= 8p + 12q + 2

Way-2 4(2p) + 4(3q) + 2 * (-2) + 2 * (3)

= 8p + 12q - 4 + 6

= 8p + 12q + 2

Way-3 4 * (2p + 3q) + 2 * (-2 + 3)

= 8p + 12q + 2

(-5g) (5k) (5k) (-5g)

(5k) 5k 5k 5k

(5k) 5k 5k 5k

-5g (5k) 5k -5g

Way-1 (-5g) + 5k + 5k + (-5g) + 5k + 5k + 5k + 5k + 5k + 5k + 5k + (-5g) + 5k + 5k + (-5g)

= -5g - 5g - 5g - 5g + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k + 5k

= -20g + 60k

Way-2 4 * (-5g) + 12 * (5k)

= -20g + 60k

Way-3 2 * (-5g) + 2 * (5k) + 8 * (5k) + 2(-5g) + 12(5k) (Typo in original: should be 4*(-5g) + 12*(5k))

= 4 * (-5g) + 12 * (5k)

= -20g + 60k

2. Simplify each of the following expressions

(a) p+p+p+p, p+p+p+q, p+q+p-q,

(b) p-q+p-q, p+q-p+q,

(c) p+q-(p+q), p-q-p-q

(d) 2d-d-d-d, 2d-d-d-c,

(e) 2d-d-(d-c), 2d-(d-d)-c,

(f) 2d-d-c-c

Sol.

(a) p+p+p+p = 4p

p+p+p+q = 3p+q

p+q+p-q = 2p

(b) p-q+p-q = 2p-2q

p+q-p+q = 2q

(c) p+q-(p+q) = p+q-p-q = 0

p-q-p-q = -2q

(d) 2d-d-d-d = -d

2d-d-d-c = -c

(e) 2d-d-(d-c) = 2d-d-d+c = c

2d-(d-d)-c = 2d-0-c = 2d-c

(f) 2d-d-c-c = d-2c

5.0Key Features and Benefits of Class 7 Maths Chapter 4 Exercise 4.2

• These Solutions contain straightforward equation-solving questions that can be solved with ease and simplicity.
• All questions have been presented following the most recent CBSE and NCERT curriculum guidelines.
• Solving NCERT Solutions improves step wise thinking and reasoning by logical deduction.
• These help prepare you for maths olympiads that have basic algebra in their syllabus.