Hi

If Amount = $100
Then Tax = 7
Total = $100.07

1. Save to: c:\xampp\htdocs\fileName
2. http://localhost/fileName.php

Bye

The actual Code is below
echo 'Hi';

define ('TAX_RATE', 0.07); // define is for Constants; in uppercase by convention
$Amount = 100; // variables start with $

echo 'If Amount = $'.$Amount; // . is used to concatenate
echo 'Then Tax = ';
echo $Amount * TAX_RATE;

echo 'Total = $';
echo $Amount + TAX_RATE;