Eh, a mathematical puzzle is being solved via brute-force. My intent was to explain briefly that the problem/puzzle is by nature computationally-intensive to the extent that brute-force is the most efficient way to solve/complete it.
That's a valid use of the word "solve". It is obviously mathematical. It is complex, as we do not have a simple way to solve it.
I get it, words can have multiple meanings. It's fine to give a clarification on the specific use here, but then move on.
Guessing a number isn't a complex mathematical number, it's just guessing a number.