function check_not_prime($num) {
   $check = false;
   for($i = $num - 1; $i > 1; $i--) {
      if($num % $i == 0) {
         $check = true;
         break;
      }
   } 
   return $check;
}
function get_next_prime($num) {
   do {
      $num++;
   } while(check_not_prime($num));
   return $num;
}

function solution(){
   $result = 2;
   $prime = 2;// first prime number
   echo $prime;
   for($i = 2; $prime <= 5000; $i++){
      $prime = get_next_prime($prime); 
	  if ($prime < 5000){
         $result += $prime;	  
	     echo " + ".$prime;
      }
   }   
   echo "<br /><strong>= ".$result."</strong>";
}