It's school holiday time, and the little ankle biters are bored, so here is a perfect opportunity to prise them away from their games consoles and get their brains and their legs working!
The title is for the parents to work on and the rest for the kids? The puzzle requires no great knowledge, just a pen and paper and a bit of (simple) work.
Whilst looking at another cache, I had an idea. Take some numbers and the signs +, -, / and *. Using the numbers in descending order and each of the signs once, what is the lowest and highest integer you can make (ignore decimals or negative numbers)? There is also one integer you can get two different ways.
Work from left to right and calculate as you go - bit like those brain training things, or simply type it in on your (PC) calculator. There are no tricks with powers or roots or brackets - just left to right using the numbers in descending order and each maths sign once.
e.g. 10-8*6/4+2 (not the right numbers) would give 5
Call the lowest answer A, the highest BC, and the "two different ways" answer D, then the cache is at
N 51 1(B+D).(C+D-A)(A+C)(C+2B)
W 00 1C.(B+C+A)(C+D-B)(B-A)
A different GPS gave me 3 less for North and 4 more for West than the solution above.