Maths Battle is a competition between two teams in solving mathematical problems. Here is the simplified version of a maths battle. For the full version see this link.

First of all, the teams are presented with the problems and given a certain time limit to solve them. While solving the problems, the team may want to discuss the solutions and strategy for the battle within the team. They may use any books or internet resources, but it is not permitted to talk about the solution to these problems with anyone except with the members of the jury. At the end of the allotted time, the actual battle begins, when the teams present the solutions of the problems in accordance with the given rules.

The battle starts with a duel between the captains. The two captains are presented with a short problem to solve; the first captain to find the correct solution decides who challenges first.

A challenge is a request for a solution to the particular problem from the list. It can be either accepted or declined. If it is accepted, the solution must be presented by a member of the team appointed by the captain. No one is allowed to present a solution more than once. Afterwards, the challenging team is asked for any objections/criticism and, if the solution happened to be wrong, may present its own solution. The correct solution means the correct answer and the correct reasoning. The final decision is at the discretion of the principal coordinator.

If the challenge is declined, then the challenging team must present their solution and the opponents are to criticise and to spot any possible mistakes. Independently of whether the presented solution is correct or not, the same team is set to challenge next time.

If one of the teams chooses not to challenge any more, then the other team may choose to show the solution to any of the remaining questions. The full marks are to be awarded if the answer is correct.

If the answer is wrong, the team scores zero marks; if the declining team spots a mistake, it scores 2 marks.

For more details on the rules see the diagram (full marks = 6 marks)