To use Numbers

This script will use three hard-coded variables upon which calculations will be made. You'll see how these values can be dynamically determined interaction with an HTML form.

Established the requisite variables.
$quantity = 30;
$price = 119.95;
$taxrate = .05;

Performe the calculations.
$total = $quantity * $price;
$total = $total + ($total * $taxrate);

Format the total
$total = number_format ($total, 2);

Print the results.
Click to see this code:

Ex: numbers.phps | numbers.php