Most easy way split array to parts
<?php
$arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
print_r(array_chunk($arr, ceil(count($arr) / 2)));
// return: [[1, 2, 3, 4, 5], [6, 7, 8, 9, 10]]
print_r(array_chunk($arr, ceil(count($arr) / 3)));
// return: [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10]]
?>