---
title: Numbers
---
## Numbers
The implementation of JavaScript's `number`s is based on the `IEEE 754` standard, often called "floating-point."
IEEE 754 Wikipedia Link
IEEE 754 Double Precision Floating Point Visualization
Number literals are expressed generally as `base-10` decimal literals.
```javascript
var foo = 47;
var bar = 47.9;
```
The leading portion of a decimal value, if `0`, is optional:
```javascript
var same = 0.47;
var stillSame = .47;
```
Similarly, the trailing portion (the fractional) of a decimal value after the `.`, if `0`, is optional:
```javascript
var a = 47.0;
var b = 47.;
```
By default, most numbers will be outputted as `base-10` decimals, with trailing fractional `0`s removed. So:
```javascript
var foo = 47.300;
var bar = 47.0;
foo; // 47.3
bar; // 47
```
Very large or very small `numbers` can be written as:
```javascript
var foo = 47e8; // 4700000000
var baz = 47e-8; // 00.00000047
```
`toExponential` method can be used to convert a `number` into its `exponential notation`.
```javascript
var foo = 47e8;
foo; // 4700000000
foo.toExponential() //"47e8"
```
Numbers have access to methods that are built into `Number.prototype`.
For Example:
`toFixed()` method formats a number with a specific number of digits to the right of the decimal.
```javascript
var foo = 47.69;
foo.toFixed(0); // "48"
foo.toFixed(1); // "47.7"
foo.toFixed(2); // "47.69"
```
>Type `Number.prototype` in your browser and see other available methods yourself.
#### More Information:
1. MDN
2. JavaScript Numbers
#### References
1. Types & grammar by Kyle Simpson.
2. ECMAScript Language Specification: 4.3.20
3. ECMAScript Language Specification: 15.7 Number Objects