DoDo and Dodo

DoDo (the abbreviation of DOuble DOzen) is an implementation of card game Twenty Four (24), popular in China and other countries with significant Chinese population, including Australia.

The standard game objective is to compose 24 our of four numbers, using four arithmetic operations. The game can be played either with 40 cards ranking from Ace (counted as 1) to 10, or with all 52 cards, where the values of Jack, Queen and King are 11, 12 and 13 resp.

As opposed to majority of other intelligent card games, "24" is a complete information game which involves luck however the players don't hide anything from each other. For that reason there is practically no need to remember cards or apply any long-term strategy, while fast counting is the only prerequisite to succeed. This makes "24" an ideal family game which helps to development arithmetic skills for primary school children, and provides entertainment for adults at the same time.

Incidentally Dodo is a name of bird species unique to a tiny island of Mauritius to the East of Africa. Dodo birds peacefully lived, eating seeds as well as fruits and nuts falling from trees. They didn't have predators apart from human settlers who eventually led them to extinction in the late 17th century. Fortunately, some illustrations, descriptions as well as remains of the birds have come to us.

Dodo was the a nickname of prominent English mathematician and writer Charles L. Dodgson, better known by his pen name Lewis Carroll, who invented a number of brain-teasing games, like a sort of "Scrabble" and popular Doublets (a.k.a. World Links or World Ladder). In his most famous novel Alice in Wonderland, Dodo bird represents the author himself and, just like the author, invents a game.


This version of game "24" encourages fast thinking. The score depends not only on the number of solved puzzles but also on the time spent on solving. If a combination has no solution, a player who figured that out is rewarded as of the puzzle is solved.

DoDo24 introduces additional operations and other extensions to the rules, such as:

DoDo24 allows playing with one or two short (40) of full (52) packs of cards. The application also provides training mode as well as an option to enter own puzzles.

A variety of customised features (settings) is available. In particular, a computer solution can presented either as sequence of operations (e.g. 6×3=18 3×2=6 18+6=24) or as an expression (6×3+3×2). Other customised features include choice of background colour or animation speed, using number or standard playing card images.

The application supports custom background music, specified as an album, artist or a playlist. The application keeps game summaries and local score tables.

This is a port of our Android release. Hopefully, the missing features (saving game, achievements, online score tables, human vs human game) will appear in the near future.

The application is designed to run with iOS 9.0 and above. It gains advantage of newer iOS features, if available.

The application requires macOS 10.13 (High Sierra) and above.


A trial copy has the only limitation: when solving time limit applies, at least 20 seconds must pass before I know! or Give up button may be pressed.

The limitation can be removed by registering your copy. Registration never expires and applies to your another compatible device. To register the application or restore your registration press Register button in the top left corner of the Main Menu page.


Dodo Image

The application uses the photograph of Dodo model at Oxford University Museum of Natural History, taken by BazzaDaRambler.

The original image (maintained by FunkMonk at Wikipedia) is distributed under Creative Commons Attribution 2.0 Generic licence. To use by this application the image has been cropped and modified.

Background Music

Don't Know composed by Paul "Snowcat" Elisarov for a demo party in 1998. Used with author's kind permission.

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