Nothing

Mathematical problem is a question about mathematical objects and structures that may require a distinct answer or explanation or proof. Examples include word problems at school level or deeper problems such as shading a map with only four colours.

In society, a problem can refer to particular social issues, which if solved would yield social benefits, such as increased harmony or productivity, and conversely diminished hostility and disruption.

See also: Wicked problem

In business and engineering, a problem is a difference between actual conditions and those that are required or desired. Often, the causes of a problem are not known, in which case root cause analysis is employed to find the causes and identify corrective actions.

In chess, a problem is a puzzle set by somebody using chess pieces on a chess board, for others to get instruction or intellectual satisfaction from determining the solution.

In theology, there is what is referred to as the Synoptic Problem, regarding the Gospels' relationship to each other.

In academic discourse a problem is a challenge to an assumption, an apparent conflict that requires synthesis and reconciliation. It is a normal part of systematic thinking, the address of which adds to or detracts from the veracity of a conclusion or idea.

An optimization problem is finding the best solution from all feasible solutions. A good example of this type of problem is the travelling salesperson problem which is based on calculating the most efficient route between many places

In computability theory a decision problem requires a simple yes-or-no answer.

In rock climbing a problem is a series of rocks that forces the climber to climb.

Let's (Ex)Change!

Youth in Action is a European Project to make the world better. Our target is to involve young people to "Take Part, Take Place, Take Care" in their own communities.
The participants of this programme come from Italy, Portugal, Hungary, Germany and Estonia.