A small math app based on a cognitive exercise developer by clinical psychologist Daniel Kahneman.

Much like the cognitive exercise, iAddThree helps users train their working memory in just a few minutes. While the game used in the clinical setting only focused on ADDING 3 to a serious of four numbers, iAddThree expands on the game with various modes (Only Add and Subtract at the moment). And to provide a bit of a challenge, as the user progresses through the game, the amount of time they have to complete each level decreases.

Pending on the mode, the user is presented with four random numbers. It is their job to add 3 to each number starting from the left (or subtract 3 in subtract mode).

Following the rules set for by Kahneman, rather than using double digits, the user is required to 'wrap around' an imaginary number line when necessary.

For example: In reality, 8 + 3 = 11 In iAddThree, 8 + 3 = 1

In the number line below, if you start at 8 and move 3 places to the right, you end up at 1.

7 -> 8 -> 9 -> 0 -> 1 -> 2

Alternatively, in 'Subtract' mode, you would reverse the direction. So if presented with 1, you would move 3 places to the left, ending up at 8.

• Add Mode: Add three to each number.
• Subtract Mode: Subtract three from each number.
• Hybrid Mode: A mix of addition and subtraction tasks.

The app is divided into two modules:

• iAddThreeCore: Hosts all the game logic, allowing efficient unit testing on Mac. This module includes classes like GameManager and GameStorageManager for handling game states and data management.
• iAddThree Main Module: Manages UI, dependencies, and integrates GoogleMobileAds, StoreKit2, and iAddThreeClassicKit XCFramework for gameplay. It features SwiftUI views like the ProUpgradeView for in-app purchases and settings management.

• Xcode 15.0 or later
• iOS 17 or later

This app is available under the MIT license. See the LICENSE file for more information.