While Calculation has the usual goal of arranging the entire contents of the deck in four stacks of thirteen cards, the suits of the cards in these stacks is irrelevant. Instead, the four stacks accept cards whose ranks differ by a specified interval. Even though the computer calculates the accepted sequences of cards, the game is still extremely challenging.

There are three areas of the screen. The deck is spread out on the left side under the button panel. Only the top card of the deck is face up and accessible. The destination stacks are located in the middle column of the layout. The ranks the top stack accepts differ by one, and the difference in the lower stacks is two, three and four. A list of the ranks accepted by the stack runs along the sides of the stack. The listing begins at the bottom of the left side and continues at the bottom of the right side. The rank which the stack currently accepts is highlighted. The destination stacks accept any card with the desired rank regardless of its suit. The four waste piles are located in the right column of layout. A waste pile can accept any card and can contain an unlimited number of cards. Transferring cards between discard piles is not allowed. The only way to remove a card from a waste pile is to move its top card to a destination stack.

To move a card, click on the card (which will highlight it) and then click on the destination. A card can be moved from the top of the deck or a waste pile to a destination stack if the card has the desired rank. Right clicking on a card will attempt to move it to a destination stack. A card can be moved from the deck to any waste pile.

Play with a high number of cards initially in the destination stacks until you have a feel for the game's strategies. Try to build reverse sequences in the discard piles. Consider reserving a waste pile solely for kings, because the cards under a king cannot be accessed until a stack is almost complete.