Look for new math problems each Monday

New problems will be placed on the contest pages each Monday, unless otherwise stated.

To submit a proposed solution, use the Submit Answer link that’s on each problem page and fill in the supplied form. Answers will be accepted until midnight, Eastern time, each Friday for each week’s problems. Contest staffers attempt to send an e-mail response to participants’ submissions within 36 hours.

If you supply a correct answer, your name, school, city, state and country (if outside the U.S.) will be displayed on the site under the current week's problem. Names of those who submit correct responses in the elementary and middle school contests will be posted only if the participant is in grade 6 or lower for the Elementary Brain Teaser or in grade 8 or lower for Middle School Madness.

Past Problems

At the end of each week, the current problem for each contest is retired to a Past Problem archive site. All past problems are available via the Past problems link on each contest site. The list of correct respondents for each problem remains with the problem after it is retired. Participants may still answer past problems. Answers to past problems will be reviewed and participants will receive an email response from staff indicating whether the supplied answer is correct. If an answer to a past problem is correct, your name will not be added to a past problem’s list of correct respondents. Each problem’s list of correct respondents is final once the problem is retired to the past problems archive.

Where are the answers?

Answers to past problems are not listed. One reason is that students and teachers have requested that we keep the past problems active. In other words, you can still submit answers to past problems.

If you would like an answer to a past problem that has been stumping you, please follow the Request a solution link on the past problem's page to receive a solution. If you request a solution to a problem, it is expected that you have previously submitted an answer to that problem. Please try the problem a few times before requesting the answer.