Increment and decrement float in PHP

gistfile1.txt

 function incrementFLoat($float){
     echo $float."\n";
   $decimal = strlen(strrchr($float, '.')) -1;
       $factor = pow(10,$decimal);
       $incremented = (($factor * $float) + 1) / $factor;
   return $incremented;
 }
 
 function decrementFLoat($float){
   // get amount of decimals
   $decimal = strlen(strrchr($float, '.')) -1;
   $factor = pow(10,$decimal);
   $decremented = (($factor * $float) - 1) / $factor;
   return $decremented;
 }