18. round()/*math function*/

You can use round() to round your number to an integer, or to round off complex floating point numbers to a specific number of decimal places. This is accomplished by passing a second, optional parameter toround(), telling it how many decimal places you want the number rounded to.

Here's an example:

// Round pi down from 3.1416...
$round = round(M_PI);
print $round;  // prints 3

// This time, round pi to 4 places
$round_decimal = round(M_PI, 4);
print $round_decimal; // prints 3.1416

NOTE: M_PI is a PHP constant that is equal to pi.