The aim of the puzzle is to use basic arithmetic operators on all of a set of numbers to arrive at the target number. This is based on a game I played with normal cards when I was young, people in the UK will recognise it as similar to Countdown, but harder as you must use all the cards. If you get stuck the computer can show you the solution, but don't give up too soon there is always a solution, unless you know better. Sounds lame but is actually quite additive when played against another person.