Holy cow, I wrote a book!
There is a mathematical card game known as
The rules are simple:
Each card has a numeric value.
Six cards are dealt face-up in the center of the table:
One card is designated as the objective card.
The object of the game is to combine the remaining five cards
in any order
using the basic four arithmetic functions so that the
result equals the objective.
A player who believes that he has found a solution,
calls Krypto! and has thirty seconds to show the solution.
For example, if the objective is 6 and the other five cards
are 1, 3, 7, 1, and 8,
then you can achieve the result by using the expression
7 + 1 - (8 / (3 + 1)) = 6.
Fractions and negative numbers
are not allowed.
As a teenager, I wondered if I could write a computer program
to solve Krypto hands,
but I never got off the ground.
Recently I discovered that, naturally,
somebody else has already done it.
My brother went to the state tournament for this game,
where we discovered that he played at a whole different level
from everybody else.
For you see, my brother could solve nearly any hand in thirty seconds or less.
Therefore, his strategy was merely to call Krypto! as soon as
the cards were dealt,
and then spend the next thirty seconds solving the puzzle.
Using this technique, he could run the table.
The scoring system for the game is such that the reward for winning
a hand is far greater than the penalty for losing one,
so the strategy pays off well.
My brother didn't go the national tournament because we didn't
want to pay for airfare and accommodations.
I vaguely recall that
the design flaw in the game was addressed at the national
tournament by converting the head-to-head competition
into a series of puzzles.
(While writing up this article,
I discovered another Krypto tournament which
redesigned the game to avoid this flaw.)