I have a question and I have a way of approaching its solution. But I don't know whether that approach is correct or not. So can I ask about whether my approach is correct or not on this site?
Provided you connect your "approach" to an actual problem to be solved, Math.SE should treat your Question as on-topic ("Is my approach correct?).
However note that the context is important. Readers will not be able to discern whether an approach is "correct" without knowing the problem setup and goal. For that matter we might want to distinguish the following (related) notions of correctness:
(1) The approach is logically sound/based on proper mathematical reasoning from the problem's setup.
(2) The approach is likely (or sure) to be successful in reaching the problem's goal.
You may have been concerned with issues of (1), but there are cases in which one first explores promising approaches that are proper reasoning only to discover that these approaches (2) can never reach the desired goal. These situations are particularly interesting, so if you are concerned about that possibility, it is well worth mentioning your suspicions in posting the Question.