  The Countdown game is one of the oldest TV show running in the world. It
started broadcasting in 1972 on the french television and in 1982 on British
channel 4, and it has been running since in both countries. The game, while
extremely popular, never received any serious scientific attention, probably
because it seems too simple at first sight. We present in this article an
in-depth analysis of the numbers round of the countdown game. This includes a
complexity analysis of the game, an analysis of existing algorithms, the
presentation of a new algorithm that increases resolution speed by a factor of
20. It also includes some leads on how to turn the game into a more difficult
one, both for a human player and for a computer, and even to transform it into
a probably undecidable problem.

Artificial Intelligence