<?php
$price = 250;
$quantity = 4;

$subtotal = $price * $quantity;   // 1000
$tax = $subtotal * 0.18;          // 180
$total = $subtotal + $tax;        // 1180

echo "Total: " . $total . PHP_EOL;
echo "Is quantity even? remainder = " . ($quantity % 2); // 0
?>