Given an integer array, I want to find the continuous subarray (containing at least one number) which has the largest sum. There are some algorithmic solutions to this here: Maximum subarray problem - Wikipedia

However, I want to be able to eyeball a solution quickly (in about 5-10 seconds) given such an integer array of 10-15 elements (so not too many where it would be infeasible to eyeball in a short amount of time, but clearly greater than 2-3 elements), doing as little explicit pencil and paper calculation as possible.

Clearly humans are different from computers, so I was wondering if anyone had any insight/strategies/tricks as to how do so quickly by eyeballing in a situation with 10-15 elements?

To clarify, I am not looking to explicitly calculate the largest sum within 5-10 seconds, but rather I’m looking for the indices where the largest sum begins and ends.