note 29030 deleted from ref.math by victor

There's no function to test whether an integer is even or odd. In PHP >4 you can do it fairly easily by testing for the modulus of the number divided by 2, like this: if ( fmod($num, 2) ) { echo "$num is odd"; } However, earlier versions lack the fmod() function, so you might have to do something like this: $half = $num/2; if ( $half - floor($half) ) { echo "$num is odd"; } Until there are built-in is_even() and is_odd() functions, the above should do the trick.