JavaScript Numbers & Math
JavaScript Numbers & Math Operations is a core JavaScript concept covering learn how JavaScript handles numbers, understand floating-point precision, This topic is essential for academic learning, board exam preparation, and developing optimized real-world code.
JavaScript Numbers
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
Precision Issues
Integers are accurate up to 15 digits. Floating point arithmetic is not always 100% accurate:
let x = 0.2 + 0.1; // 0.30000000000000004
Fix: To solve this, multiply and divide: let x = (0.2 * 10 + 0.1 * 10) / 10;
NaN - Not a Number
NaN is a reserved word indicating that a number is not a legal number.
let x = 100 / "Apple"; // x is NaN
console.log(isNaN(x)); // true
Number Methods
toString(): Returns a number as a string.toFixed(n): Returns a string with the number written withndecimals (e.g.,9.656.toFixed(2)->"9.66").Number(str): Converts a variable to a number.parseInt(str): Parses a string and returns a whole number.
The Math Object
The JavaScript Math object allows you to perform mathematical tasks on numbers.
| Method | Description |
|---|---|
Math.round(x) | Rounds to the nearest integer. |
Math.ceil(x) | Rounds up to the nearest integer. |
Math.floor(x) | Rounds down to the nearest integer. |
Math.sqrt(x) | Returns the square root. |
Math.abs(x) | Returns the absolute value. |
Math.random() | Returns a random number between 0 and 1. |
Math.ceil(4.4); // 5
Math.floor(4.7); // 4
Random Integer
To get a random integer between 0 and 10:
Math.floor(Math.random() * 11);