Your use of push is ...incorrect. See the docs for push() and you'll see that it requires more than one argument.

As for a recommendation on how to add the elements of two arrays, I would do it with List::MoreUtils, using the pairwise() subroutine. Here's from the POD:

pairwise BLOCK ARRAY1 ARRAY2
Evaluates BLOCK for each pair of elements in ARRAY1 and ARRAY2 and returns a new list consisting of BLOCK's return values. The two elements are set to $a and $b. Note that those two are aliases to the original value so changing them will modify the input arrays.

@a = (1 .. 5);
@b = (11 .. 15);
@x = pairwise { $a + $b } @a, @b;   # returns 12, 14, 16, 18, 20
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That's really the right tool for the job, and will lead to clearer code.