Roughly speaking, any board or card game is a comparison of one object's properties and abilities with another. Let's take two cards; one is white and holds the number 1, the other is black and holds the number 2. If the most obvious rules are applied, the second card is more powerful, so it wins because two is greater than one.
This is the basis of a strategic game called Stratego (http://en.wikipedia.org/wiki/Stratego). It uses simple arithmetic comparisons to determine the winner of battle between two game pieces (each of them can represent soldiers, officers, or special items such as bombs). In most cases, the piece with a higher rank defeats its opponent; for example, a colonel, who ranks at 8 easily overpowers a sergeant who ranks at 4. The logic is pretty elementary and very descriptive, but it has not much intrigue as there are no unexpected turns. This problem can be fixed by introducing extra conditions that work on special occasions.
Let's return to our example...