Died: September 7, 1985 in Palo Alto, California, USA
Pólya worked in probability, analysis, number theory,
geometry, combinatorics and mathematical physics while at the University of
Budapest, Brown University, and Stanford University.
If you can't solve a problem, then there is an easier problem you can
solve: find it.
How to Solve It
Summary taken from G. Polya, "How
to Solve It", 2nd ed., Princeton University Press, 1957, ISBN 0-691-08097-6.
UNDERSTANDING THE PROBLEM
First. You have to understand the problem.
What is the unknown? What are the data? What is the condition?
Is it possible to satisfy the condition? Is the condition sufficient to
determine the unknown? Or is it insufficient? Or redundant? Or
Draw a figure. Introduce suitable notation.
Separate the various parts of the condition. Can you write them down?
DEVISING A PLAN
Second. Find the connection between the data and the unknown. You
may be obliged to consider auxiliary problems if an immediate connection
cannot be found. You should obtain eventually a plan of the solution.
Have you seen it before? Or have you seen the same problem in a slightly
Do you know a related problem? Do you know a theorem that could
Look at the unknown! And try to think of a familiar problem
having the same or a similar unknown.
Here is a problem related to yours and solved before. Could you use
it? Could you use its result? Could you use its method? Should you
introduce some auxiliary element in order to make its use possible?
Could you restate the problem? Could you restate it still differently?
Go back to definitions.
If you cannot solve the proposed problem try to solve first some related
problem. Could you imagine a more accessible related problem? A more general
problem? A more special problem? An analogous problem? Could you solve a
part of the problem? Keep only a part of the condition, drop the other part;
how far is the unknown then determined, how can it vary? Could you derive
something useful from the data? Could you think of other data appropriate to
determine the unknown? Could you change the unknown or data, or both if
necessary, so that the new unknown and the new data are nearer to each
Did you use all the data? Did you use the whole condition? Have you
taken into account all essential notions involved in the problem?
CARRYING OUT THE PLAN
Third.Carry out your plan.
Carrying out your plan of the solution, check each step. Can you
see clearly that the step is correct? Can you prove that it is correct?
Fourth.Examine the solution obtained.
Can you check the result? Can you check the argument?
Can you derive the solution differently? Can you see it at a glance?
Can you use the result, or the method, for some other problem?