THE CALCULATOR

(aka The Math Game)

The Calculator is an original card game that makes math fun. I thought of it a number of years ago and have played it countless times with children of various ages and they have all loved it. The game can be played alone or with two or more people and is fun for all ages, starting at the point where kids know basic mathematics.

To Start: From a standard deck of cards, remove the face cards (jacks, queens, kings and jokers) as the game needs only aces through tens. Ace = 1 in this game. Deal each player five cards. No other cards will be used. Before looking at the cards, somebody picks a target- a number from 50 to 99.

To Play: Use each card once and any combination of addition, subtraction, multiplication and division to get as close as possible to the target. Pencil and paper are not allowed!

Example: Someone chooses a target of 73. Player A is dealt...

He or she may think of: 8 + 2 = 10; 10 x 7 = 70; 70 - 4 + 6 = 72. There are other possibilities- including a way to get 73- which is part of the fun and mental exercise. Limit the game to one, two or three minutes, depending on the skill level of those playing. (This doesn't mean having to use a timer or stopwatch, I've always played with a general sense of when enough time has passed.) After this, each player demonstrates his or her calculation to the others.

Remember, each card must be used and only one time.

To Score: In the above example, the player gets 1 point since the calculation of 72 is one off the target of 73. Higher or lower than the target does not make a difference. Getting the target exactly scores a bonus of -1 instead of 0 points. Play a set of five games. The winner is the player with the least points after the set of games; -5 is the best possible total. (Youngsters not yet up to speed with negative numbers can score a zero for hitting the target exactly.)

Tie-Breaker: If two players end the set of games with, say, seven points each, then the one with the lowest score in any round is the winner. If they are still tied, then the one with the best score from any two rounds is the winner. If still tied (I haven't experienced this, but figure I should include the possibility), the two can play single games till one gets a better score.

A solo player can add his or her points from a set of games and play against that personal score.

Choose one or more of the following to make the game even more fun.

A) Shorten the time-limit and use a timer or stopwatch to be exact.

B) Lightning bonus; score an extra -1 when a player gets the target within 3-5 seconds of looking at the cards. New option added May 2011!

C) Use exponents and square roots. In our example, the player can go: 8 to the power of 2 = 64; 64 + 7 = 71; 71 + 6 - 4 = 73! To do a square root, one must use the number 2, either the card 2 or other cards forming 2 (as in, card 6 minus card 4 = 2). Then with the number 2, 9, 16, etc., one can go: the square root (2) of 25 = 5...

D) Rather than deal each player five cards, lay five cards face up on the table for all players to use. This requires each player to reveal his calculation on a piece of paper, otherwise the second player can simply say the same thing as the first (in a case where the second player did not have as good a mental calculation).

Rather than a timer, play Option C until a player says she has a calculation. All others must then put down their pens and the one who called it reveals her calculation. The trick with this version is for each player to write the first calculation that comes to mind, even if one feels he can get closer to the target (and, until someone calls it, he should continue thinking of a better calculation and writing that, too). This way, he can choose to call it or at least have the option of showing a calculation if another player calls it before him. Players who do not have a calculation or choose not to show one because it is way off the target automatically get a score of 5 higher than the worst score by any other player in that round.

Let me know what you think and your comments, especially new rules and variations, may be posted here. Email me at (Sorry, it's not clickable in order to reduce spam.)

Help spread the word:

Have fun!

- Robbie

July, 2010