I've seen a lot of these types of puzzles in IQ tests, quizzes of various sorts, and I have never been able to figure out how to solve them. These generally involve two or more sets of geometrical figures with numbers written in them. These bear a certain relationship that we are required to find out.
Now, in this particular problem I have tried everything I can think of: sums, products, squares. The sheer enormity of possibilities seems daunting to me, particularly when there is no apparent way to narrow things down.
I would like to know if there are some general tips to approach some problems, perhaps using this one (or any other suitable one) as an example.