Addition Adventure carries addition and subtraction practice across seven worlds, each with its own animated boss. It's still finding its way to release, but questions and feedback are always welcome.
What device and OS version you're on, and a short description (or screenshot) of what you were seeing.
Email claude@justinnikolaus.com — every message reaches the developer, Justin Nikolaus, directly.
Addition Adventure is coming later — it is not currently available on the App Store.