Exercise: Find Discount

We created two variables to store the original price of a product in dollars and the discount percentage applied to that price.

Use these two variables and arithmetic operations to compute and print the discount amount in dollars.

Example:

For example, if price was 150 and discount was 10, the answer would be 15.

Why? Because the discount is 10%. And 10% of 150 dollars is 15 dollars.

Introduction

In this lesson, we will learn how to calculate the discount amount given the original price of a product and the discount percentage. This is a common task in various applications, such as e-commerce websites, where discounts are frequently applied to products.

Understanding how to perform this calculation is essential for developers working on financial applications, shopping platforms, or any system that involves price adjustments.

Understanding the Basics

Before diving into the solution, let's understand the basic concepts:

Price: The original cost of the product before any discounts.
Discount Percentage: The percentage by which the original price is reduced.
Discount Amount: The actual amount deducted from the original price.

To calculate the discount amount, we use the formula:

Discount Amount = (Price * Discount Percentage) / 100

This formula helps us determine the portion of the price that corresponds to the given discount percentage.

Main Concepts

Let's break down the key concepts and techniques involved:

Variables: We will use variables to store the price and discount percentage.
Arithmetic Operations: We will perform multiplication and division to calculate the discount amount.

Here's how to apply these concepts:

// Define the price and discount percentage
let price = 150;
let discount = 10;

// Calculate the discount amount
let discountAmount = (price * discount) / 100;

// Print the discount amount
console.log(discountAmount); // Output: 15

Examples and Use Cases

Let's look at a few more examples to solidify our understanding:

// Example 1
let price1 = 200;
let discount1 = 20;
let discountAmount1 = (price1 * discount1) / 100;
console.log(discountAmount1); // Output: 40

// Example 2
let price2 = 50;
let discount2 = 5;
let discountAmount2 = (price2 * discount2) / 100;
console.log(discountAmount2); // Output: 2.5

These examples demonstrate how the formula can be applied to different prices and discount percentages.

Common Pitfalls and Best Practices

When calculating discounts, avoid these common mistakes:

Forgetting to divide by 100 when calculating the percentage.
Using incorrect variable names, which can lead to confusion and errors.

Best practices include:

Using clear and descriptive variable names.
Adding comments to explain the purpose of each step in the code.

Advanced Techniques

For more advanced scenarios, you might need to handle additional factors such as:

Applying multiple discounts sequentially.
Calculating the final price after applying the discount.

Here's an example that combines these advanced techniques:

// Define the price and multiple discount percentages
let price = 300;
let discount1 = 10;
let discount2 = 5;

// Calculate the first discount amount
let discountAmount1 = (price * discount1) / 100;

// Calculate the new price after the first discount
let newPrice = price - discountAmount1;

// Calculate the second discount amount
let discountAmount2 = (newPrice * discount2) / 100;

// Calculate the final price after both discounts
let finalPrice = newPrice - discountAmount2;

console.log(finalPrice); // Output: 256.5

Code Implementation

Here is the complete code implementation for calculating the discount amount:

// Define the price and discount percentage
let price = 150;
let discount = 10;

// Calculate the discount amount
let discountAmount = (price * discount) / 100;

// Print the discount amount
console.log(discountAmount); // Output: 15

Debugging and Testing

When debugging and testing your code, consider the following tips:

Check for edge cases, such as a discount percentage of 0 or 100.
Ensure that the price and discount percentage are valid numbers.

Example test cases:

// Test case 1: No discount
let price = 100;
let discount = 0;
let discountAmount = (price * discount) / 100;
console.log(discountAmount); // Output: 0

// Test case 2: Full discount
price = 100;
discount = 100;
discountAmount = (price * discount) / 100;
console.log(discountAmount); // Output: 100

Thinking and Problem-Solving Tips

When approaching problems related to discounts, consider these strategies:

Break down the problem into smaller steps, such as calculating the discount amount and then the final price.
Use clear and descriptive variable names to make your code more readable.
Practice with different scenarios to build your confidence and understanding.

Conclusion

In this lesson, we covered how to calculate the discount amount given the original price and discount percentage. We explored the basic concepts, provided examples, discussed common pitfalls, and introduced advanced techniques. Mastering these concepts is essential for developers working on financial applications or any system involving price adjustments.

Keep practicing and exploring further applications to strengthen your understanding and skills.

Additional Resources

For further reading and practice, consider the following resources: