The inverse of this strategy also works well sometimes: try to solve a more general (i.e. "harder") version of the problem. Examples: * https://math.stackexch

The inverse of this strategy also works well sometimes: try to solve a more general (i.e. "harder") version of the problem. Examples: * https://math.stackexchange.com/questions/899109/problems-that-become-easier-in-a-more-general-form https://math.stackexchange.com/questions/899109/problems-tha... * https://mathoverflow.net/questions/21214/particular-problem-solved-by-solving-a-more-general-problem https://mathoverflow.net/questions/21214/particular-problem-... The second link has the neat particular example of showing that something is nonzero by showing that it is odd, which I quite like.