<?php
 
$list = [
	['number' => 3],
	['number' => 2],
	['number' => 45],
];
// 1st example
echo array_sum(array_column($list, 'number')), PHP_EOL;
 
// 2nd example
echo array_reduce($list, function ($carry, $item) {
	return $carry += $item['number'];
}), PHP_EOL;
 
// 3rd example
array_walk($list, function ($item) use (&$sum) {
	$sum += $item['number'];
});
echo $sum, PHP_EOL;
 
// 4th example
array_map(function ($item) use (&$sum2) {
	$sum2 += $item['number'];
}, $list);
echo $sum2, PHP_EOL;

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