Support
Help for our games — a collection of kid-friendly, offline number, logic & board-game puzzles for iPhone and iPad.
Contact us
Have a question, found a bug, or need help with a purchase? Email us — we usually reply within 1–2 business days. Please mention the game name, your device model, and iOS version.
You can also open an issue at github.com/htphuc1994/mathduel-site/issues.
Frequently asked questions
The app works with no internet — is that normal?
Yes. Our games are fully offline by design. The internet is only ever used for an optional purchase or restore, which the App Store handles.
How do I change the language?
Tap the 🌐 globe button on the start screen and pick from the list — our games support 11 languages.
Does the game cost anything?
It depends on the title: some are a simple one-time paid app, and some are free with an optional one-time in-app unlock. There are no subscriptions.
How do I unlock the full version (games that offer it)?
On the start screen, look for an Unlock button (or tap a locked option). A short one-time parental check appears, then the App Store purchase sheet.
I already bought the unlock — how do I get it on a new device?
Open the unlock screen and tap Restore Purchase. Purchases are tied to your Apple ID and restore for free.
Do you collect any data?
Our games collect no personal data and have no accounts. See each game’s Privacy Policy for the details.
I’m having another problem.
Please email htphuc.cs@gmail.com with the game name, your device model, and iOS version, and we’ll help.