The application provides two configuration types: Game Options and Settings.
Game Options are set up when game starts and remain unchanged throughout the game. They consist of Conditions and Rule variations.
The period of time allowed to solve a puzzle.
In Training mode time limit can be disabled by selecting None.
Number of packs to use: 1 or 2. For example, if 2 full packs (without Zero cards) are used, the deck contains 104 cards.
A solvable set is selected by generate and test method, so it may take a while until a puzzle is found, especially if the magic number is different from 24.
When player enters solution, the last line is completed automatically. This increases solving time by 1.5 seconds. The option is enabled by default.
Allows to increase the challenge by changing target value from 24 to a different figure in range 18 to 30.
Allow an Ace (or One, if numeric cards are used) to be treated as either 1 or 11. When entering solution, tap Ace/One card and hold until it is accepted as 11.
In particular, the rule allows to solve the all-Ace (all-One) combination: 11+11+1+1 or (11+1)*(1+1). A less obvious example: set 10 5 1 1, unsolvable under standard rules, gets two solutions after adding 1-11 rule: 11+11+10/5 and (11+1)*10/5
One zero card is added to a pack. If standard playing cards are used, Zero card is represented by Joker.
If Merge is enabled, a Zero card can provide a certain convenience, for example 100/4-1, or 120/5.
Accepts an intermediate result as a common fraction.
Set 8 8 3 3 (solution: 8/(3-8/3)) has been mentioned in Wikipedia. Another example: 10 5 5 2, solution 5*(5-2/10). The following solution of puzzle 7 7 5 1 needs both Fractions and 1-11 to be enabled: 7*(5-11/7).
Allows an intermediate result to be below zero.
To be honest, the only purpose to include this option is to avoid questions why it isn't there :). It appears to us that any solution involving negative numbers can be replaced by a similar one where negative values do not appear, therefore allowing negatives only increases computation time.
Enable raising to power operation, e.g. 2^3=8.
Merge (or concatenation) is an operation of writing one number after another: 1#2=12 1#23=123.
Example: the only solution of puzzle 10 5 5 3 involves Merge operation: 10#5=105 105:5=21 21+3=24 (or written as an expression 105:5+3).
Merge is inapplicable, if at least one of operands is a fraction, or second operand is negative.
Allows merge if one of operands is an intermediate result.
For example, the already mentioned puzzle 10 5 1 1 has a solution 1#(10-1)+5, valid only if Merge+ is enabled.
As opposed to Game Options, Settings can be changed at any moment by selecting Change Settings from the Game Menu. Settings are grouped in Appearance and Music.
The appearance of cards in game: Playing Cards or Numbers.
Sequence option makes the solution intuitive and easy to understand. In turn, Expression option provides a compact and fast way to demonstrate a solution as well as show additional solutions, if several solutions exist.
This feature allows you to give each sign a more intuitive look.
For example, instead of asterisk sign (*) used by default for multiplication you may chose the real multiplication sign (×). Similarly, division sign (÷) can be used instead of slash (/) for division.
The colour used to tint the background.
Animation speed (Slow, Normal, Fast) or Off for no animation.
Turns off movement of cards during animation.
Start application in full-screen mode. Note that full-screen mode can be enabled or disabled at any time with Ctrl + ⌘ + F.
Swap left and right panels to get the buttons at left.
Volume of sound effects in the range from 0 (off) to 100.
Enable sound effects and music even when ringer is disabled with mute switch of the device.
Specifies whether the music is played only during the game, only between the games, all time, or turned off.
The volume of background music in the range from 1 to 100. As opposed to device volume keys system volume control, this sets up music volume exclusively for the application.
Grants access to user's music file to play them in the background. This permission can also be granted or revoked using system setting Privacy - Media & Apple Music - DoDo24
Pre 9.3 releases of iOS do no require such a permission. Otherwise, if permission is not granted, the application can only play internal music, so two following items are unavailable.
If custom music is enabled, showsShow a page to select an album, artist or a play list for the background music. Play lists created automatically by iTunes are referred as smart playlists.
If enabled, the music tracks are played in random order, otherwise they are picked up according to the default order. Appears if severa music files are selected to play.
If enabled (assumed by default) the application displays each music title before playback.