Commercial Mathematics Formulas - Mathematics Class 8

Learn important formulas from the Commercial Mathematics chapter of Class 8 Mathematics with examples, variables and applications.

📐 Commercial Mathematics Formulas

Complete collection of formulas with explanations and examples

Compound Interest Amount

$$A = P(1 + R/100)^n$$

Description: Compound Interest Amount is a standard relation used in commercial-mathematics.

Variables:

  • n = number of years

Example:

Apply the relation: A = P(1 + R/100)^n

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.
  • Exam relevance: ssc, banking

Discount

$$discount = marked price - selling price$$

Description: Discount is a standard relation used in commercial-mathematics.

Example:

Apply the relation: discount = marked price - selling price

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Loss

$$loss = cost price - selling price$$

Description: Loss is a standard relation used in commercial-mathematics.

Example:

Apply the relation: loss = cost price - selling price

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Profit

$$profit = selling price - cost price$$

Description: Profit is a standard relation used in commercial-mathematics.

Example:

Apply the relation: profit = selling price - cost price

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Profit Percentage

$$profit percent = profit / cost price x 100$$

Description: Profit Percentage is a standard relation used in commercial-mathematics.

Example:

Apply the relation: profit percent = profit / cost price x 100

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.

Simple Interest

$$SI = PRT / 100$$

Description: Simple Interest is a standard relation used in commercial-mathematics.

Variables:

  • P = principal
  • R = rate percent per year
  • T = time in years

Example:

Apply the relation: SI = PRT / 100

Identify the known values, substitute them in the relation, and solve for the unknown quantity.
Result depends on the substituted values.

Applications:

  • Use this when the quantities in the relation are known and the missing quantity is required.
  • Exam relevance: ssc, railway, banking

Quick Reference

Compound Interest Amount: $A = P(1 + R/100)^n$
Discount: $discount = marked price - selling price$
Loss: $loss = cost price - selling price$
Profit: $profit = selling price - cost price$
Profit Percentage: $profit percent = profit / cost price x 100$
Simple Interest: $SI = PRT / 100$

💡 Worked Examples

Step-by-step solutions using Commercial Mathematics formulas

Example 1: Area of Circle

Circle Area Formula
Problem:

Find the area of a circle with radius 7 cm.

Solution:
  1. Given: r = 7 cm
  2. Apply formula: A = πr²
  3. Substitute: A = π × 7²
  4. Calculate: A = π × 49 = 49π cm²
  5. Approximate: A ≈ 49 × 3.14159 ≈ 153.94 cm²
Answer:

Area = 49π cm² ≈ 153.94 cm²

🎯 Practice Problems

Try these problems to test your understanding:

Practice Problem 1

Solve the quadratic equation: x² - 7x + 12 = 0

Practice Problem 2

Find the area of a circle with diameter 14 cm.

Practice Problems

Check Your Formula Recall

Write each formula once, define every variable, then solve one direct substitution problem before moving to mixed questions.

Apply Commercial Mathematics

Pick two formulas from this page and create your own values for the variables. Verify units and signs before calculating.

Derivation Notes

Focus on how the formula is built, not only the final expression. Derivations help with board-exam reasoning and multi-step application questions.

  • Start from the definition or identity used in the chapter.
  • Write assumptions clearly before substituting values.
  • Track units through each step to catch calculation mistakes.

Where These Formulas Are Used

Board Exam Problems

Use these formulas for direct numerical questions, proof-based steps, and short-answer reasoning in Mathematics.

Competitive Practice

Memorize the condition of use for each formula so you can identify the right expression quickly under timed practice.

Related Formula Chapters

Algebra And Factorisation 3 formulas Commercial Mathematics 6 formulas Data Handling 1 formulas Linear Equations 1 formulas Mensuration 4 formulas Proportion 2 formulas

These Commercial Mathematics formulas help students revise concepts quickly and apply equations accurately in exam-style problems.

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