A mathematical problem is a problem that is amenable to being analyzed, and possibly solved, with the methods of mathematics. This can be a realworld problem, such as computing the orbits of the planets in the solar system, or a problem of a more abstract nature, such as Hilbert's problems. It can also be a problem referring to the nature of mathematics itself, such as Russell's Paradox.
Contents 
Informal "realworld" mathematical problems are questions related to a concrete setting, such as "Adam has five apples and gives John three. How many has he left?". Such questions are usually more difficult to solve than regular mathematical exercises like "5 âˆ’ 3", even if one knows the mathematics required to solve the problem. Known as word problems, they are used in mathematics education to teach students to connect realworld situations to the abstract language of mathematics.
In general, to use mathematics for solving a realworld problem, the first step is to construct a mathematical model of the problem. This involves abstraction from the details of the problem, and the modeller has to be careful not to lose essential aspects in translating the original problem into a mathematical one. After the problem has been solved in the world of mathematics, the solution must be translated back into the context of the original problem.
Abstract mathematical problems arise in all fields of mathematics. While mathematicians usually study them for their own sake, by doing so results may be obtained that find application outside the realm of mathematics. Theoretical physics has historically been, and remains, a rich source of inspiration.
Some abstract problems have been rigorously proved to be unsolvable, such as squaring the circle and trisecting the angle using only the compass and straightedge constructions of classical geometry, and solving the general quintic equation algebraically. Also provably unsolvable are socalled undecidable problems, such as the halting problem for Turing machines.
Many abstract problems can be solved routinely, others have been solved with great effort, for some significant inroads have been made without having led yet to a full solution, and yet others have withstood all attempts, such as Goldbach's conjecture and the Collatz conjecture. Some wellknown difficult abstract problems that have been solved relatively recently are the fourcolour theorem, Fermat's Last Theorem, and the PoincarĂ© conjecture.
