A brain teaser is a form of

puzzle A puzzle is a game, problem, or toy that tests a person's ingenuity or knowledge. In a puzzle, the solver is expected to put pieces together ( or take them apart) in a logical way, in order to find the solution of the puzzle. There are differe ...

that requires thought to solve. It often requires thinking in unconventional ways with given constraints in mind; sometimes it also involves

lateral thinking Lateral thinking is a manner of Problem solving, solving problems using an indirect and creativity, creative approach via reasoning that is not immediately obvious. Synonymous to thinking outside the box, it involves ideas that may not be obtai ...

. Logic puzzles and

riddle A riddle is a :wikt:statement, statement, question, or phrase having a double or veiled meaning, put forth as a puzzle to be solved. Riddles are of two types: ''enigmas'', which are problems generally expressed in metaphorical or Allegory, alleg ...

s are specific types of brain teasers. One of the earliest known brain teaser enthusiasts was the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

Archimedes Archimedes of Syracuse ( ; ) was an Ancient Greece, Ancient Greek Greek mathematics, mathematician, physicist, engineer, astronomer, and Invention, inventor from the ancient city of Syracuse, Sicily, Syracuse in History of Greek and Hellenis ...

. He devised mathematical problems for his contemporaries to solve.

Example

:Q: ''If three hens lay three eggs in three days, how many eggs does a (statistical) hen lay in one day?'' :A1: ''One third.'' (Note: 3 hens = 3 eggs / 3 days → 3 hens = (3 / 3) (eggs / days) → 1 hen = (1 / 3) (egg / days)) :A2: ''Zero or one'' (it's hard to lay a third of an egg). One can argue about the answers of many brain teasers; in the given example with hens, one might claim that all the eggs in the question were laid in the first day, so the answer would be three. :Q: ''Mary's father has five daughters: 1. Nana, 2. Nene, 3. Nini, 4. Nono. What is the name of the fifth daughter?'' :A: ''Mary''. The first four daughters all have names with the first 4 vowels, so if someone does not think about the question, they may say the name with the fifth vowel, Nunu. The answer was given at the beginning of the question (i.e., Mary's father has five...) :Q: ''What appears once in a minute, twice in a moment, but never in a thousand years?'' :A: The letter "M". :Q: ''I am the beginning of the end, the beginning of eternity, and the end of all time?'' :A: The letter "E".

Intuition

The difficulty of many brain teasers relies on a certain degree of fallacy in human intuitiveness. This is most common in brain teasers relating to

conditional probability In probability theory, conditional probability is a measure of the probability of an Event (probability theory), event occurring, given that another event (by assumption, presumption, assertion or evidence) is already known to have occurred. This ...

, because the causal human mind tends to consider absolute probability instead. As a result, controversial discussions emerge from such

problem Problem solving is the process of achieving a goal by overcoming obstacles, a frequent part of most activities. Problems in need of solutions range from simple personal tasks (e.g. how to turn on an appliance) to complex issues in business an ...

s. One of the famous brain teasers is the

Monty Hall problem The Monty Hall problem is a brain teaser, in the form of a probability puzzle, based nominally on the American television game show ''Let's Make a Deal'' and named after its original host, Monty Hall. The problem was originally posed (and solved ...

. Another (simpler) example of such a brain teaser is the Boy or Girl paradox.

References

{{DEFAULTSORT:Brain Teaser Puzzles

Example

Intuition

See also

References