求和两个数组的内容

I am just start learning the coding. I have two sets of array, $arr1 and $arr2.

$arr1 = array(1, 2);
$arr2 = array(3, 4, 5, 6, 7, 8, 9, 10);

From these two array, I need to sum the items of $arr1 with two pairs[(3, 4), (5, 6), (7, 8)] of items from $arr2, so that my third array is like

$arr3 = array(10, 14, 18, 22)

Can anybody help me solve this?

Thank you.

<?php

    $sumFirstArr = 0;
    $arr3;

    $arr1 = array(1, 2);
    $arr2 = array(3, 4, 5, 6, 7, 8, 9, 10);

    foreach($arr1 as $x)$sumFirstArr += $x;

    for($i=1; $i<count($arr2); $i+=2){
        $arr3[] =  $sumFirstArr +($arr2[$i-1]+$arr2[$i]);
    }

    print_r($arr3);

?>

Output:

Array (
  [0] => 10 
  [1] => 14 
  [2] => 18 
  [3] => 22
)

Use array_chunk() to split an array into chunks, and use array_sum() to caculate sum of chunked array and $arr1.

<?php
$arr1 = array(1, 2);
$arr2 = array(3, 4, 5, 6, 7, 8, 9, 10);
$arr3 = array_map(function($value) use ($arr1){
    return array_sum($value) + array_sum($arr1);
}, array_chunk($arr2, 2));
print_r($arr3);

Result:

Array
(
    [0] => 10
    [1] => 14
    [2] => 18
    [3] => 22
)