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id: "69be7cd21b1028d43db3b611"
title: "Expressions using Letter-Numbers"
board: "CBSE"
curriculum: "CBSE"
class: "Class 7"
subject: "Mathematics"
book: "Ganita Prakash"
chapter: "Expressions using Letter-Numbers"
chapter_slug: "expressions-using-letter-numbers"
canonical_url: "https://www.edzy.ai/cbse-class-7-mathematics-ganita-prakash-expressions-using-letter-numbers"
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last_updated: "2026-06-20"
---

# Expressions using Letter-Numbers
In this chapter we will explore a concise way of expressing mathematical relations and patterns, which aids in understanding and explaining their validity.

---

## Knowledge Snapshot

| Field | Details |
| :--- | :--- |
| Class | Class 7 |
| Subject | Mathematics |
| Book | Ganita Prakash |
| Chapter | Expressions using Letter-Numbers |
| Pages | 81-105 |

---

## Chapter Summary

### Short Summary
This chapter focuses on representing mathematical relationships using letter-numbers and algebraic expressions, enhancing the clarity and understanding of these concepts.

### Detailed Summary
The chapter introduces letter-numbers, using examples to illustrate how they express mathematical relations concisely. We explore instances where specific expressions relate to real-life situations, such as age problems and costs of items. The chapter emphasizes the use of algebraic expressions in concise formulations, detailing various applications like calculating costs and perimeters, ultimately showcasing how letter-numbers simplify the expression of mathematical relationships.

---

## Topic-Wise Explanation

### Algebraic Modeling in Real Life
The chapter illustrates how letter-numbers create algebraic expressions to model real-life scenarios, like age differences and pricing.

### Summary of Key Concepts
Letter-numbers and algebraic expressions are summarized as tools for succinctly representing mathematical statements?

### The Notion of Letter-Numbers
Letters used to represent numbers in expressions, termed letter-numbers, streamline mathematical communication.

### Revisiting Arithmetic Expressions
This section revisits arithmetic basics through algebraic representations, aiding in understanding their applications.

### Omission of the Multiplication Symbol in Algebraic Expressions
Expressions like $a 	imes b$ can be simplified to $ab$. This convention streamlines expression writing.

### Simplification of Algebraic Expressions
The chapter elaborates on methods to simplify algebraic expressions to enhance their usability.

### Pick Patterns and Reveal Relationships
Understanding patterns in numbers through expressions highlights the systemic relationships between various mathematical entities.

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## Core Ideas

| Idea | Explanation |
| :--- | :--- |
| Letter-Numbers | Symbols used to represent numerical values in expressions. |
| Algebraic Expressions | Mathematical phrases built using letter-numbers. |

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## Key Concepts

| Concept | Meaning |
| :--- | :--- |
| Expression | A combination of numbers and letters representing a value. |
| Formula | A special kind of expression that exhibits a relationship between different variables. |

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## Important Points for Revision
* Aftab’s age can be represented as $a$ and Shabnam’s as $s$. The relationship is $s = a + 3$.
* The expression for matchsticks using $n$ Ls is $2 	imes n$.
* The cost of coconuts is expressed as $c 	imes 35$ and jaggery as $j 	imes 60$.
* Perimeter of a square is $4 	imes q$.
* Simplifying algebraic expressions helps in understanding their relations better.
* Letter-numbers can effectively simplify calculations and expressions.
* Algebraic expressions can represent multiple scenarios with changes in variables.

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## Vocabulary and Glossary

| Word / Phrase | Meaning |
| :--- | :--- |
| Letter-numbers | Symbols for representing numerical values in algebraic expressions. |
| Algebraic expression | A mathematical statement that combines numbers and variables. |

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## Practice Questions

### Short Answer Questions
1. What expression represents Shabnam's age if Aftab's age is $a$?
2. How many matchsticks are needed for $n$ Ls?
3. Write the expression for the total cost if 8 coconuts are bought.
4. What is the perimeter of a square with side length $q$?
5. Simplify the expression $3a + 2b$.

### Long Answer Questions
1. Derive the expression for Aftab’s age given Shabnam’s age.
2. Explain how to derive the total amount spent on coconuts and jaggery in algebraic form.
3. Solve for the perimeter of a triangle if all sides are equal using algebraic expressions.
4. Discuss how letter-numbers help in understanding arithmetic operations.

---

## Related Concepts
* Algebraic expressions
* Letter-numbers

---

## Source Attribution

| Field | Value |
| :--- | :--- |
| Source | Edzy |
| Reference Type | examSubjectBookChapter |
| Reference ID | 69be7cd21b1028d43db3b611 |
| Canonical URL | https://www.edzy.ai/cbse-class-7-mathematics-ganita-prakash-expressions-using-letter-numbers |
| Markdown URL | https://www.edzy.ai/okf/chapter/cbse-class-7-mathematics-ganita-prakash-expressions-using-letter-numbers.md |