#!/usr/bin/perl
use CGI; $q = new CGI; print $q->header, $q->start_html; 
$message = $q->param('message'); 
$n1      = $q->param('n1'); 
$n2      = $q->param('n2'); 
$answer  = $q->param('answer'); 

   if ($message) {
     if ($n1 + $n2 == $answer) { $message = "Good job. "; } 
     else { $message = "Nope, the answer was: " . ($n1 + $n2); } 
   } else { $message = "Welcome"; } 
   $n1 = int(rand(100)) - 50; 
   $n2 = int(rand(100)) - 50;  

print qq{<form method=POST> 
  $message <p> 
  What is $n1 + $n2 ? <p> 
  Type your answer here: <input type="text" name="answer"> <p> 
  Press <input type="submit" value="Proceed"> to send it in.   
  <input type="hidden" name="message" value="$message"> 
  <input type="hidden" name="n1"      value="$n1"> 
  <input type="hidden" name="n2"      value="$n2"> 
</form> };