PHP Basic computation with formatting number

code to paste:

<?php

$rate_per_day = 250;

$days_of_work = 10;

$cash_advance = 100;


$gross_salaryy = $rate_per_day * $days_of_work;

$gross_salary = number_format($gross_salaryy, 2, '.', ',');

$net_payy = $gross_salaryy - $cash_advance;

$net_pay = number_format($net_payy, 2, '.', ',');

echo '<br><br><p align="center">Your rate per day is:'.$rate_per_day.'</p>';
echo '<p align="center">Your days work is:'.$days_of_work.'</p>';
echo '<p align="center">Your cash advance is:'.$cash_advance.'</p>';
echo '<p align="center">Your gross pay is:'.$gross_salary.'</p>';
echo '<p align="center">Your net pay is:'.$net_pay.'</p>';

?>