If I have a number like -7 stored in a variable how can I modify a date in php by this amount. Here's what I have so far;
<?php
$the_date = '16 Mar 2018';
$test_sum = '-7';
$date = $the_date;
$date = strtotime($date);
$date = strtotime($test_sum, $date);
echo date('d M Y', $date);
?>
But this just output's the initial date value.
strtotime