JavaScript Numbers

In JavaScript, numbers are a data type that represent both integers and floating-point values. JavaScript numbers are always stored as double-precision floating-point numbers.

1. Number Types

Integers: Whole numbers, positive or negative.
```
let intNum = 42;
```
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Floating-point Numbers: Numbers with decimals.
```
let floatNum = 3.14;
```
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Exponential Notation: Large or small numbers can be represented using exponential notation.
```
let expNum = 5e6;  // 5000000
```
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2. Number Properties

MAX_VALUE: Largest possible number in JavaScript.

console.log(Number.MAX_VALUE);  // Output: 1.7976931348623157e+308

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MIN_VALUE: Smallest possible positive number in JavaScript.
```
console.log(Number.MIN_VALUE);  // Output: 5e-324
```
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NaN: Represents a value that is “Not-a-Number”.
```
let result = 0 / 0;
console.log(result);  // Output: NaN
```
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Infinity: Represents infinity, which is greater than any number.
```
console.log(1 / 0);  // Output: Infinity
```
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-Infinity: Represents negative infinity.
```
console.log(-1 / 0);  // Output: -Infinity
```
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3. Number Methods

toString(): Converts a number to a string.

let num = 123;
console.log(num.toString());  // Output: "123"

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toFixed(): Formats a number to a specified number of decimal places.
```
let num = 5.6789;
console.log(num.toFixed(2));  // Output: "5.68"
```
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toPrecision(): Formats a number to a specified length.

let num = 5.6789;
console.log(num.toPrecision(3));  // Output: "5.68"

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valueOf(): Returns the primitive value of a number.

let num = new Number(123);
console.log(num.valueOf());  // Output: 123

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4. Number Conversion

parseInt(): Parses a string and returns an integer.

let num = parseInt('123.45');
console.log(num);  // Output: 123

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parseFloat(): Parses a string and returns a floating-point number.
```
let num = parseFloat('123.45');
console.log(num);  // Output: 123.45
```
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Number(): Converts a value to a number.

let num = Number('123.45');
console.log(num);  // Output: 123.45

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5. Checking for Numbers

isNaN(): Checks if a value is NaN.

console.log(isNaN('Hello'));  // Output: true

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isFinite(): Checks if a value is a finite number.
```
console.log(isFinite(10 / 2));  // Output: true
```
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Number.isInteger(): Checks if a value is an integer.
```
console.log(Number.isInteger(42));  // Output: true
```
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6. Special Number Values

NaN: Represents a computational error or an undefined mathematical result.
```
console.log(0 / 0);  // Output: NaN
```
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Infinity and -Infinity: Result from division by zero or a number too large for JavaScript to handle.
```
console.log(1 / 0);  // Output: Infinity
console.log(-1 / 0);  // Output: -Infinity
```
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7. Example: Basic Arithmetic Operations

let a = 10;
let b = 3;
console.log(a + b);  // Output: 13
console.log(a - b);  // Output: 7
console.log(a * b);  // Output: 30
console.log(a / b);  // Output: 3.3333
console.log(a % b);  // Output: 1

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Summary

Numbers in JavaScript can represent both integers and floating-point values.
Methods like toFixed(), parseInt(), and Number() help in converting and formatting numbers.
Special values like NaN and Infinity handle exceptional cases in numerical computations.

These capabilities make JavaScript numbers versatile for a wide range of mathematical operations and data manipulation tasks.