Polya's problem solving scheme

• What is given?
• What is to find?
• What are the conditions?
• Make (if possible) a sketch of the proof?
• Introduce the notations?
• Identify known and unknown parameters)

Make a plan of a proof

• Do you know any related problem?
• Do you know any theorem or formula that can help?
• Can you reformulate the problem, e.g. by retrieving the Definition?
• Can you solve a relative problem or some more specific one?
• Can you solve a part of a problem?

Execute the plan

• Control every step of the transformation.
• Check with which goal you are perfoming the transformation and why is this step correct.

Look back

• Verify the solution.
• Make sure the succession of the solution steps is clear.
• Could you possibly reach your goal in a better way?
• Could you possibly solve further problems in the same way?