This would reduce the number of possible combinations to eight: 444, 446, 464, 466, 644, 646, 664, and 666.

As they show, the number of different combinations in such a system is given by the ordered Bell numbers.

The number of new combinations ran out in 2008.

The number of possible combinations is more than the whole population could get through in a lifetime.

The total number of combinations is a surprising 15,680, although only one can be used in any given battle.

In smaller cases it is possible to count the number of combinations.

"We're going to work a number of combinations there," Lewis said.

This is about 0.3% of the total number of possible combinations.

The key to its success is attributed to the large number of cards and interesting combinations.

As such, there are an incredible number of combinations to be explored.