Guess can be roughly divided into the following forms: ① analogy guess; ② Inductive conjecture; ③ Symmetry conjecture; (4) Forging conjecture; ⑤ Inverse conjecture.

The way to realize conjecture can be exploration, experiment, analogy, induction, construction, association, aesthetics and their combination. Mathematical conjecture has certain rules, such as analogy and induction, which should be based on mathematical knowledge and experience. Before proving a mathematical problem, guess the content of the problem; Before making a detailed proof, we must first guess the idea of proof.