Math in JavaScript

JavaScript provides comprehensive mathematical capabilities through arithmetic operators and the built-in Math object. Learn how to perform calculations, generate random numbers, and solve real-world math problems.

🧮 Basic Arithmetic Operations

JavaScript provides all standard arithmetic operators for mathematical calculations. These operators follow standard mathematical precedence rules.

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Arithmetic Operators:

+ - Addition
- - Subtraction
* - Multiplication
/ - Division
% - Modulus (remainder)
** - Exponentiation (ES6)

Increment/Decrement:

++x - Pre-increment (increment then return)
x++ - Post-increment (return then increment)
--x - Pre-decrement
x-- - Post-decrement

📊 The Math Object

JavaScript provides a built-in Math object with properties and methods for mathematical constants and functions. No need to create it - it's available globally.

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// Math Object - Built-in Mathematical Functions
console.log("Math Object Properties:");
console.log("Math.PI =", Math.PI);
console.log("Math.E =", Math.E);  // Euler's number
console.log("Math.SQRT2 =", Math.SQRT2);  // Square root of 2

console.log("\nRounding Methods:");
console.log("Math.round(4.7) =", Math.round(4.7));    // Nearest integer
console.log("Math.round(4.4) =", Math.round(4.4));
console.log("Math.ceil(4.2) =", Math.ceil(4.2));      // Round up
console.log("Math.floor(4.9) =", Math.floor(4.9));    // Round down
console.log("Math.trunc(4.9) =", Math.trunc(4.9));    // Remove decimal

console.log("\nPower and Roots:");
console.log("Math.pow(2, 3) =", Math.pow(2, 3));      // 2 to the power 3
console.log("Math.sqrt(25) =", Math.sqrt(25));        // Square root
console.log("Math.cbrt(27) =", Math.cbrt(27));        // Cube root

console.log("\nTrigonometric Functions (in radians):");
console.log("Math.sin(Math.PI/2) =", Math.sin(Math.PI/2));
console.log("Math.cos(Math.PI) =", Math.cos(Math.PI));
console.log("Math.tan(Math.PI/4) =", Math.tan(Math.PI/4));

console.log("\nLogarithmic Functions:");
console.log("Math.log(10) =", Math.log(10));          // Natural log
console.log("Math.log10(100) =", Math.log10(100));    // Base 10 log
console.log("Math.log2(8) =", Math.log2(8));          // Base 2 log

Common Methods:

Math.round() - Round to nearest integer
Math.ceil() - Round up
Math.floor() - Round down
Math.trunc() - Remove decimal part

Power & Roots:

Math.pow(x, y) - x to the power y
Math.sqrt(x) - Square root
Math.cbrt(x) - Cube root

Trigonometry:

Math.sin(x) - Sine (radians)
Math.cos(x) - Cosine
Math.tan(x) - Tangent

🎲 Random Numbers & Utilities

The Math.random() method generates pseudo-random numbers. For random integers in a specific range, we need to do some calculations.

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// Random Numbers and Utilities
console.log("Random Numbers:");
console.log("Math.random() =", Math.random());  // Random between 0-1
console.log("Math.random() =", Math.random());
console.log("Math.random() =", Math.random());

console.log("\nRandom Integers:");
function getRandomInt(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

console.log("Random between 1-10:", getRandomInt(1, 10));
console.log("Random between 1-10:", getRandomInt(1, 10));
console.log("Random between 1-10:", getRandomInt(1, 10));

console.log("\nAbsolute Values and Signs:");
console.log("Math.abs(-5.5) =", Math.abs(-5.5));      // Absolute value
console.log("Math.abs(10) =", Math.abs(10));
console.log("Math.sign(-10) =", Math.sign(-10));      // Sign function
console.log("Math.sign(0) =", Math.sign(0));
console.log("Math.sign(10) =", Math.sign(10));

console.log("\nMin/Max Values:");
console.log("Math.max(10, 20, 5, 30) =", Math.max(10, 20, 5, 30));
console.log("Math.min(10, 20, 5, 30) =", Math.min(10, 20, 5, 30));

// Find min/max in array
let numbers = [15, 8, 42, 23, 17];
console.log("Math.max(...numbers) =", Math.max(...numbers));
console.log("Math.min(...numbers) =", Math.min(...numbers));

💡 Generating Random Integers:

Math.random() returns a decimal between 0 (inclusive) and 1 (exclusive).
To get an integer between min and max:Math.floor(Math.random() * (max - min + 1)) + min

💰 Practical Examples

Let's apply our math knowledge to solve real-world problems like price calculations, distance measurement, and currency conversion.

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// Practical Math Examples
console.log("=== PRICE CALCULATOR ===");

// Calculate discounted price
function calculateDiscount(originalPrice, discountPercent) {
  const discountAmount = originalPrice * (discountPercent / 100);
  const finalPrice = originalPrice - discountAmount;
  return Math.round(finalPrice * 100) / 100; // Round to 2 decimal places
}

console.log("Original: $99.99, 20% off:", "$" + calculateDiscount(99.99, 20));
console.log("Original: $49.50, 15% off:", "$" + calculateDiscount(49.50, 15));

console.log("\n=== DISTANCE CALCULATOR ===");

// Calculate distance between two points (Pythagorean theorem)
function calculateDistance(x1, y1, x2, y2) {
  const dx = x2 - x1;
  const dy = y2 - y1;
  return Math.sqrt(dx * dx + dy * dy).toFixed(2);
}

console.log("Distance between (0,0) and (3,4):", calculateDistance(0, 0, 3, 4));
console.log("Distance between (1,2) and (4,6):", calculateDistance(1, 2, 4, 6));

console.log("\n=== CURRENCY CONVERTER ===");

// Convert currency with fee
function convertCurrency(amount, exchangeRate, feePercent = 1.5) {
  const fee = amount * (feePercent / 100);
  const converted = (amount - fee) * exchangeRate;
  return Math.round(converted * 100) / 100;
}

console.log("Convert $100 to EUR (rate: 0.85):", convertCurrency(100, 0.85), "EUR");
console.log("Convert $250 to GBP (rate: 0.75):", convertCurrency(250, 0.75), "GBP");

console.log("\n=== RANDOM PASSWORD GENERATOR ===");

function generatePassword(length = 8) {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*';
  let password = '';
  for (let i = 0; i < length; i++) {
    const randomIndex = Math.floor(Math.random() * chars.length);
    password += chars[randomIndex];
  }
  return password;
}

console.log("8-character password:", generatePassword());
console.log("12-character password:", generatePassword(12));

📝 Try These Challenges:

Modify the discount calculator to apply tax after discount
Create a function to calculate compound interest
Build a BMI (Body Mass Index) calculator
Create a temperature converter (Celsius ↔ Fahrenheit)

📋 Math Object Quick Reference

Constants:

Math.PI - 3.141592653589793
Math.E - Euler's number (2.718)
Math.SQRT2 - √2 (1.414)
Math.LN2 - Natural log of 2

Min/Max:

Math.min(a, b, c...) - Smallest value
Math.max(a, b, c...) - Largest value
Math.abs(x) - Absolute value
Math.sign(x) - Sign (-1, 0, or 1)

Other Useful:

Math.log(x) - Natural logarithm
Math.exp(x) - e^x
Math.hypot(x, y) - √(x² + y²)
Math.random() - Random 0-1

← Date & Time DOM Introduction →

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JavaScript Tutorial

Math in JavaScript

🧮 Basic Arithmetic Operations

Arithmetic Operators:

Increment/Decrement:

📊 The Math Object

Common Methods:

Power & Roots:

Trigonometry:

🎲 Random Numbers & Utilities

💡 Generating Random Integers:

💰 Practical Examples

📝 Try These Challenges:

📋 Math Object Quick Reference

Constants:

Min/Max:

Other Useful:

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