Number Sense is a freemium, ad-free math app. Core lessons, learner profiles, progress, games, and rewards work locally on the device. Optional Premium billing is processed by the App Store or Google Play. We do not sell personal information, show behavioral ads, or use third-party advertising or tracking SDKs.

A learner profile contains a nickname, grade from 1 through 10, and a bundled color avatar. Progress and downloaded reviewed lesson videos stay on the device. Number Sense does not ask for a learner photo, school, ZIP code, email address, phone number, or precise location.

Voice Coach and known-friend battle codes are unavailable until a verified grown-up approves them for that learner through our parental-consent provider, PRIVO. We store the consent reference, approved feature scopes, and security credentials needed to enforce that decision. A learner is never placed in an open directory or public matchmaking queue.

After approval and a learner action, up to 15 seconds of microphone audio may be sent through our server to a Cloudflare-only voice service. Audio and transcript text are processed in memory to return a math response and are not intentionally stored by Number Sense. At most 600 characters of curated lesson context are sent. Production voice remains disabled until the required provider terms and child-privacy review are complete.

A learner may create or enter a random, single-use code shared with a friend they already know. Codes expire after 15 minutes, pending invitations after 24 hours, and completed battle results after 30 days. There is no chat, public profile search, social feed, open matchmaking, or rematch directory.

Reviewed lessons play only as MP4 files hosted at videos.mindmath.org or downloaded privately to the device. Number Sense does not embed YouTube or arbitrary web pages. Camera access is requested only to scan a Number Sense battle code. Microphone access is requested only when an approved learner starts Voice Coach. The app does not request photo-library or notification permission.

Raw audio and transcript text are not retained. Connected learner records are de-identified after 12 months of inactivity. A grown-up can delete a learner in Profiles, which removes local progress and requests deletion or de-identification of connected records. For help, contact privacy@mindmath.org.

Privacy questions: privacy@mindmath.org. Product support: support@mindmath.org. United States launch service is provided through mindmath.org/numbersense.