call round $num=…[;$mode=…[;$precision=…]]
$precision = The optional number of decimal digits to round to.
$mode = what happens to a half(.5)
one of the following
PHP_ROUND_HALF_UP   ; default action
PHP_ROUND_HALF_DOWN 
PHP_ROUND_HALF_EVEN ; round to the even number
PHP_ROUND_HALF_ODD  ; round to the odd number