- print_r: documentation ( source)
- array_values: documentation ( source)
<?php
$items = array(array('amount' => 50), array('amount' => 60), array('amount' => 100), array('amount' => 25), array('amount' => 30), array('amount' => 89), array('amount' => 90), array('amount' => 120), array('amount' => 16), array('amount' => 38));
$itemsSum = array_values($items);
//$itemsSum = array_sum(array_values(array_values($items)));
//echo $itemsSum;
print_r($itemsSum);