In scientific disciplines, a toy problem is a problem that is not of immediate scientific interest, yet is used as an expository device to illustrate a trait that may be shared by other, more complicated, instances of the problem, or as a way to explain a particular, more general, problem solving technique.

For instance, while engineering a large system, the large problem is often broken down into many smaller toy problems which have been understood in good detail. Often these problems distill a few important aspects of complicated problems so that they can be studied in isolation. Toy problems are thus often very useful in providing intuition about specific phenomena in more complicated problems.

See, for example:

• Santa Fe Ant Trail problem
• Secretary problem
  Secretary problem
  The secretary problem is one of many names for a famous problem of theoptimal stopping theory.The problem has been studied extensively in the fields ofapplied probability, statistics, and decision theory...
  
  
• Missionaries and cannibals problem
  Missionaries and cannibals problem
  The missionaries and cannibals problem, and the closely related jealous husbands problem, are classic river-crossing problems. The missionaries and cannibals problem is a well-known toy problem in artificial intelligence, where it was used by Saul Amarel as an example of problem...
  
  
• Monkey and Banana problem
  Monkey and banana problem
  The monkey and banana problem is a famous toy problem in artificial intelligence, particularly in logic programming and planning.-Formulation of the problem:...
  
  
• N-Queens problem
• Firing squad synchronization problem
  Firing squad synchronization problem
  The firing squad synchronization problem is a problem in computer science and cellular automata in which the goal is to design a cellular automaton that, starting with a single active cell, eventually reaches a state in which all cells are simultaneously active...