Chapter 4: EXPRESSIONS USING LETTER-NUMBERS

Math • Class 7

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Chapter Analysis

Beginner10 pages • English

Quick Summary

The chapter 'Expressions Using Letter-Numbers' introduces students to the concept of algebraic expressions and their utility in representing mathematical relationships. It covers how to use letters to denote numbers in expressions, forming the basis of algebraic thinking. The chapter includes various examples and problems related to patterns and simple algebraic expression formation and simplification. Through exercises, students learn to write and simplify expressions describing real-life situations.

Key Topics

  • Introduction to letter-numbers and algebraic expressions
  • Forming algebraic expressions to describe patterns
  • Simplification of algebraic expressions
  • Omission of the multiplication sign in algebra
  • Practical examples using algebraic expressions
  • Constructing and solving algebraic expressions for real-world scenarios

Learning Objectives

  • Understand and express mathematical relationships using algebraic expressions.
  • Learn to simplify and manipulate algebraic expressions.
  • Identify and describe patterns using algebra.
  • Develop skills in translating word problems into algebraic expressions.
  • Apply the distributive property in simplifying expressions.

Questions in Chapter

Shabnam is 3 years older than Aftab. When Aftab is 10 years old, how old is Shabnam?

Answer: Shabnam is 13 years old.

Page 81

Express the age of Aftab who is 3 years younger than Shabnam.

Answer: Aftab's age = Shabnam's age - 3.

Page 81

Describe the expression for the pattern of matchsticks Parthiv makes by placing Ls next to each other.

Answer: Number of matchsticks = 2 × number of Ls.

Page 82

Simplify the expression: 4(x + y) - y

Answer: 4x + 3y

Page 91

Are the expressions 5u and 5 + u equal?

Page 92

Additional Practice Questions

If b is 4 times the value of a, express the relationship using algebra.

easy

Answer: b = 4a.

Simplify the algebraic expression: 3p + 4p - 2q + q.

medium

Answer: The simplified expression is 7p - q.

If the perimeter of a square is expressed as 4a, find the side of the square.

easy

Answer: The side of the square is a.

Write the expression to describe the total cost if x coconuts cost ₹35 each and y kilograms of jaggery cost ₹60 each.

medium

Answer: Total cost = 35x + 60y.

Ajay has n marbles. He buys 5 more marbles each day. Write an expression for the total marbles after d days.

hard

Answer: Total marbles = n + 5d.