This question is based on the five, three-digit numbers given below. (Left)…

In digit-position numerical-puzzle questions, every multi-digit number is treated as an ordered sequence of digit positions - first, second, third, and so on, read strictly left to right, exactly as fixed by the worked example given with the question. Solving such a question always follows the same three-stage method: identify the number(s) required by the stated ranking property (such as highest or lowest value) among the given set, extract the specified digit position from that number, and then combine the extracted digits using the stated operation, again performed strictly left to right.

1. The five given three-digit numbers are 589, 598, 415, 514, and 597.

2. Comparing all five values shows 598 is the greatest of the five, since 598 > 597 > 589 > 514 > 415.

3. Reading 598 left to right gives first digit 5, second digit 9, third digit 8 - so the third digit of the highest number is 8.

4. Comparing all five values again shows 415 is the smallest of the five, since 415 < 514 < 589 < 597 < 598.

5. Reading 415 left to right gives first digit 4, second digit 1, third digit 5 - so the second digit of the lowest number is 1.

6. Adding the two extracted digits left to right, as instructed, gives 8 + 1 = 9.

Re-ordering the five numbers independently in increasing order, 415 < 514 < 589 < 597 < 598, confirms 598 as the highest and 415 as the lowest; re-reading their digits again gives third digit 8 (of 598) and second digit 1 (of 415), so the sum 8 + 1 = 9 is confirmed by this independent re-check.

The resultant is 9.