# roundn
> Round a numeric value to the nearest multiple of 10^n.
## Usage
```javascript
var roundn = require( '@stdlib/math/base/special/roundn' );
```
#### roundn( x, n )
Rounds a `numeric` value to the nearest multiple of `10^n`.
```javascript
// Round a value to 2 decimal places:
var v = roundn( 3.141592653589793, -2 );
// returns 3.14
// If n = 0, `roundn` behaves like `round`:
v = roundn( 3.141592653589793, 0 );
// returns 3.0
// Round a value to the nearest thousand:
v = roundn( 12368.0, 3 );
// returns 12000.0
```
## Notes
- When operating on [floating-point numbers][ieee754] in bases other than `2`, rounding to specified digits can be **inexact**. For example,
```javascript
var x = 0.2 + 0.1;
// returns 0.30000000000000004
// Should round to 0.3...
var v = roundn( x, -16 );
// returns 0.3000000000000001
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var roundn = require( '@stdlib/math/base/special/roundn' );
var x;
var n;
var v;
var i;
for ( i = 0; i < 100; i++ ) {
x = (randu()*100.0) - 50.0;
n = roundn( randu()*5.0, 0 );
v = roundn( x, -n );
console.log( 'x: %d. Number of decimals: %d. Rounded: %d.', x, n, v );
}
```
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985