Numbers are used to represent numerical values. They are written with or without decimals.

let x = 3.14;
let y = 3;

JavaScript has only one type of number. Numbers can be written with or without decimals.

let x = 3.14;    // A number with decimals
let y = 3;       // A number without decimals

JavaScript has a number of built-in methods for working with numbers.

The toString() method returns a number as a string.

let x = 123;
console.log(x.toString()); // "123"

The toFixed() method formats a number with a specific number of digits after the decimal point.

let x = 9.656;
console.log(x.toFixed(0)); // 10
console.log(x.toFixed(2)); // 9.66
console.log(x.toFixed(4)); // 9.6560

The toPrecision() method formats a number to a specified length.

let x = 9.656;
console.log(x.toPrecision()); // 9.656
console.log(x.toPrecision(2)); // 9.7
console.log(x.toPrecision(4)); // 9.656
console.log(x.toPrecision(6)); // 9.65600

The valueOf() method returns the primitive value of a number.

let x = 123;
console.log(x.valueOf()); // 123

The parseInt() method parses a string and returns an integer.

let x = "10";
console.log(parseInt(x)); // 10

The parseFloat() method parses a string and returns a floating point number.

let x = "10.33";
console.log(parseFloat(x)); // 10.33

The isNaN() method returns true if the value is NaN, and false otherwise.

let x = NaN;
console.log(isNaN(x)); // true

The isFinite() method returns true if the value is a finite number, and false otherwise.

let x = 10 / 0;
console.log(isFinite(x)); // false

The Number() method returns a number, converted from its argument.

let x = true;
console.log(Number(x)); // 1

The MAX_VALUE property returns the largest number possible in JavaScript.

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

The MIN_VALUE property returns the smallest number possible in JavaScript.

console.log(Number.MIN_VALUE); // 5e-324

The POSITIVE_INFINITY property represents positive infinity.

console.log(Number.POSITIVE_INFINITY); // Infinity

The NEGATIVE_INFINITY property represents negative infinity.

console.log(Number.NEGATIVE_INFINITY); // -Infinity

The EPSILON property represents the difference between 1 and the smallest floating point number greater than 1.

console.log(Number.EPSILON); // 2.220446049250313e-16

The MIN_SAFE_INTEGER property returns the minimum safe integer in JavaScript.

console.log(Number.MIN_SAFE_INTEGER); // -9007199254740991

The MAX_SAFE_INTEGER property returns the maximum safe integer in JavaScript.

console.log(Number.MAX_SAFE_INTEGER); // 9007199254740991

:::info 📝 Note The Number object is a wrapper object allowing you to work with numerical values. A Number object is created using the Number() constructor.

let x = new Number(123);
console.log(x); // [Number: 123]

:::

In this section, you learned how to create and manipulate numbers in JavaScript. You also learned about the different methods that can be used to manipulate numbers. In the next section, you will learn about strings in JavaScript.