Hi, Why the answer is 5 of the code below?

Question

https://code.sololearn.com/wMY5z0Vjjk60/?ref=app

Answer 1

$i value will be vary 1 to 10 as use of the loop
${"a"."$i"} will make the number as $a1 to $a10 and you are priting the value of $a1+$a10-$a6 so this value is came by this condition
${"a"."$i"}=11-$i;
For $i = 1
$a1 =11-1 = 10
$a10 = 11-10 = 1
$a6 = 11-6 = 5
You are printing this value
echo $a1+$a10-$a6;
So output will be 10+1-5 = 11-5 = 6
So output is 6

Answer 2

I found if we change $a6, the result is 6,

Answer 3

Thank You very much, STEASY!