Unable to echo variable in value (HTML tag), help its my assignment

... So what im trying to do is, to get the output as Discount price & Total saved, i have written all the code but im not getting the out put, kindly somebody help. I don't understand why its happening.

PHP code is:

<?php 

if (isset($_GET['submit']))     {
    
    $price = $_GET["price"];
    $percent = $_GET["percent"];
    $discount = $price-($price*$percent/100);
    $saved = $price-$discount;
}
?>

I want to show the output in simple HTML tag value, but its not working.

<table align="center">
<tr>
<td>Discounted Price: </td>
<td><input type="text" name="discount" value='<?php echo $discount; ?>'></td>
</tr>
<tr>
<td>Total Saved: </td>
<td><input type="text" name="totalsaved" value='<?php echo $saved; ?>'></td>
</tr>
</table>