Coming back from the UK on the plane, reading the FT, I got to reading about sudoku. An engaging little game which uses a form of mathematics (but in an easy, no adding up or long-division-type way). The approach to the game is called heuristics. I had to reach for a dictionary. You can too at dictionary.com but here is the definition: Link.
Sounds like trial and error to me - which is the approach I use for so many things in life, which I now have a cool new name for.