The cache is NOT at the posted coordinates!
To find and log this cache, you must first solve the puzzle below.
This puzzle was inspired by, and thus dedicated to my brother, [Redacted]. He is a math teacher, but if you've ever seen him do math in his free time, you probably wouldn't know it. I have redacted his name in case his superintendent is reading this page and finds out he's bad at math. Please Observe: Look Keenly – I'm Unconvinced Searching for a hidden name is worth your time, because it would be far too hard to find!
Anyways, the other night, he was looking at some geocaching stats. He messaged me to say that I, with 900 finds, was only 600 behind the 100th place Ohio cacher who had 15,000. Now, most of you can probably see what his mistake was, right? 900 finds is 600 shy of 1,500, not 15,000. I actually need 14,100 finds to catch up, so I still have a long way to go! Unfortunately (for him) his little math error amused me enough to inspire this puzzle, so his mistake will live in infamy!
To solve this puzzle, you will have to figure out what math error is being made below. You will then have to repeat the error when solving the final problem. For example, let's say you were given 10 – 5 + 3 = (-2) and then asked to solve 8 + 10 - 6. Well, it appears the mistake was that the first problem was solved right-to-left, because 3 + 5 – 10 = (-2), so to solve the second problem, you would also need to work backwards. Thus, 8 + 10 – 6 = 4.
See, it's so easy even [Redacted] could do it! Now it's your turn! This one may be just a smidge harder than the example above.
Problem 1:
48 + 15 – 6 = 131
Problem 2:
48 + (15 – 6) = 75
Problem 3:
48 – 6 + 15 = 232
Problem 4:
48 – (6 + 15) = 17
Final Problem:
(( 760 + 607 – ( 6 + 24 ) * 19 ÷ 5 - 32 ) * 4 ÷ ( 859 + 850 )) – 23,926,909 = ?
Enter the correct "incorrect" solution to the final problem into the checker.

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Disclaimer: My brother's math error occurred around midnight, which is about 3 hours past his bedtime. He's actually a pretty good math teacher when he gets his beauty sleep!