Countdown (game show) in Haskell

"Countdown" is a game where the players have to take numbers and operations ($+$, $-$, $*$, $/$) and find a way to arrive to a given result.

For instance, with 25, 50, 75, 100, 3 and 6 can you compute 952?

Well this one is a bit difficult to find. Let's see if Haskell can find a solution.

• the source code in Literate Haskell: countdown.lhs
• the document rendered in Markdown: countdown.md