Last updated: 8 September 2026
MathChirp (“the app”) is developed and published by Nguyen Van Sang (“we”, “us”). You can contact us at sang89vh@icloud.com.
MathChirp is a learning app for children on iPhone, iPad and Android — counting and arithmetic, letters and English, colours, animals and shapes, drawing, colouring, handwriting practice and flashcards — normally used with a parent or teacher nearby. Because it is directed at children, we have deliberately configured it to avoid personalised advertising and behavioural tracking. The app has no sign-up, and never asks for a name, an email address, or any other contact detail.
The app saves only the following, and only on the device itself:
None of this is sent to us. There is no account, and none of it is synced or backed up to any server. Deleting the app deletes all of it.
We do not collect or receive your name, email address, phone number, postal address, location, contacts, photos, calendar, health data or browsing history. The app contains no analytics and no crash reporting. We do not build a profile of you or your child, and we do not sell or share personal information.
Answering out loud is optional. If you tap the microphone button, the app uses the speech recognition built into the device — Apple’s on iPhone and iPad, Google’s on Android — to turn the spoken number into an answer. Depending on the device and its settings, Apple or Google may process that audio on their own servers; this is covered by Apple’s privacy policy and Google’s privacy policy, and the system tells you so when it asks for permission.
We never receive, store or transmit that audio ourselves. The recognised number is used only to check the current answer and is then discarded. If you decline the microphone or speech recognition permission, the app stays fully playable using the on-screen keypad — voice input is a convenience, not a requirement.
MathChirp is free to use. It offers one optional rewarded video advert: you may choose to watch one in exchange for extra plays. Watching is never required, and no advert interrupts a round of questions. There is also an optional subscription, described in the next section, which removes adverts entirely.
Adverts are supplied by Google AdMob. Because this app is directed at children, every advert request is tagged for child-directed treatment and limited to general-audience (rating “G”) content. In practice this means Google serves non-personalised adverts and does not use the advertising identifier (IDFA) for this app. The app therefore never shows Apple’s App Tracking Transparency prompt, and does not track you across other companies’ apps or websites. On Android the equivalent identifier is removed from the app altogether, so the advertising ID is not available to the app or to Google for it.
To deliver an advert, Google receives technical information such as the device model, operating system version, the approximate region derived from the IP address, and which ad slot was requested. Google’s handling of this is described at policies.google.com/technologies/partner-sites.
MathChirp Plus is an optional subscription, sold monthly or yearly. It gives unlimited daily play and removes adverts. On some devices it also unlocks cloud-written practice text, described in the next section.
Everything the app teaches is in the free version. No learning activity is behind the subscription, and running out of daily plays never locks the app — waiting until the next day is always a valid way to keep playing.
Payment is handled entirely by the App Store or Google Play, depending on where you installed the app. We never see or receive your card number, billing address or any other payment detail. We are told only whether a subscription is currently active. You can view, change or cancel the subscription in your Apple Account settings or in Google Play, not through us; cancelling stops the renewal and the app returns to the free version.
Newer phones and tablets can write practice text — story problems, hints and encouragement — using an AI model built into the device, at no cost and without anything leaving it. Older devices have no such model. For those, and only those, MathChirp can ask its own server, which asks OpenAI, to write that text instead.
This happens only when both are true: a subscription is active, and a parent has agreed to it on a screen that explains what it does. It is off until then, and it can be turned off again at any time. If it is off, or unavailable, the app writes from its own built-in templates and nothing else changes.
What is sent: numbers the app itself generated, and sentences the app itself wrote. Nothing else.
What is never sent: anything your child said, wrote, drew, photographed or scored. No microphone audio, no handwriting, no camera image, no transcript, no test result, and no identifier for you or your child. This is a limit built into the app rather than a promise about how we behave: the parts of the app that handle a child’s own voice, handwriting, camera and scores have no route to the server at all.
Requests reach OpenAI through our own server, which passes on no account, device or advertising identifier. Because what is sent contains no personal information, there is nothing in it that identifies you or your child.
Everything except the optional rewarded advert and the optional cloud AI writing works without a network connection: generating questions, reading them aloud, the keypad, handwriting, scoring and the results screen.
We hold no personal data about you on any server. Our cloud AI server passes on generated practice text and keeps no profile of you or your child, and there is no account to attach anything to. So there is nothing for us to retain, export or delete on your behalf. Everything the app stores is local to the device; removing the app removes it.
MathChirp is intentionally made for children. We do not knowingly collect personal information from anyone, of any age. There is no sign-up, no profile, no messaging, no user-generated content, no social features and no link out to the open web from inside the app. Advertising is restricted as described above. If you are a parent or guardian and have a question about any of this, please write to sang89vh@icloud.com.
If this policy changes, the “last updated” date at the top changes with it.