<?php function period($numerator,$denominator){ $array=array(); $modulo=$numerator%$denominator; $counter=1; while($modulo!=0){ if($array[$modulo-1]!=0)break; $array[$modulo-1]=$counter; $modulo*=10; $explode=explode('.',$modulo/$denominator); $period.=$explode[0]; $modulo%=$denominator; $counter++; } if($modulo!=0){ $part=explode('.',$numerator/$denominator); return $part[0].'.'.substr($period,0,$array[$modulo-1]-1).'('.substr($period,$array[$modulo-1]-1).')'; } else return $numerator/$denominator; } echo period(3870,36).'<br>'; echo period(397,259).'<br>'; echo period(183498,36).'<br>'; echo period(333,496); ?>