Privacy Policy

Last updated: October 12, 2026

1) Who we are

The App is a time-driven spaced repetition system (SRS) for practicing multiplication facts. The App uses Firebase services (Authentication, Firestore, Cloud Functions, Storage, and (where available) Analytics and App Check) to provide accounts, sync progress, and enable features like session history and scene customization.

2) Information we collect

We collect information in three main ways: (a) information you provide, (b) information generated by your use of the App, and (c) technical data collected by our service providers.

A. Account and profile information

• Historical anonymous account identifier

  If you used the App before anonymous sign-in was retired, we may retain the Firebase account ID and progress that was stored for that historical account. Signed-out sample practice does not create a Firebase account.

• Sign-in information

  If you create or use an identified account, we may receive your email address and/or a provider identifier from Google, Apple, or an email-link sign-in flow (depending on what you use).

• School-authorized learner sessions

  A teacher-owned learner practicing through a class link or a home code does not have a parent account. A remembered session — a home-code enrollment, or an earlier class sign-in that the learner or an adult chose to keep on that device — stores an opaque per-session resume secret and the learner's display name on the device so the App can resume it; the secret has no authority once a teacher or a connected parent ends it. A shared-device classroom sign-in without that choice does not store a resume secret and ends when the browser session ends or after a period of inactivity.

• Username and settings

  We store a display username (which may be randomly generated) and preferences like theme and session length.

B. Learning and usage data (App content)

The App is designed to adapt to performance. We store learning progress and session data, which may include:

• Practice data

  Your multiplication facts, review history, spaced-repetition scheduling fields (e.g., next due time, box/interval/ease factor), and performance stats such as correct/incorrect counts and response-time averages.

• Session summaries

  Information about sessions (e.g., start/end time, session length, and aggregate results).

• Scene builder data

  If you use the scene builder, we may store scene metadata and user-uploaded images/assets in Firebase Storage.

C. Technical and analytics data

Our hosting and backend providers (including Firebase) may collect technical information such as device/browser type, IP address, app interaction events, and crash/diagnostic signals. Where Firebase Analytics is enabled and supported by your environment, Analytics may collect usage data to help us understand performance and improve the App. We use this for product analytics, not advertising or sale of personal information.

D. Public game leaderboards (information you choose to post)

Some free multiplication games on our public pages (for example, the Sixty Second Sweep) have leaderboards. After finishing a game, a player may choose to post their time. Posting is optional, needs no account, and asks only for a nickname the player types and, if they wish, a US state or country chosen from a list. The nickname, the optional state or country, the game time, and the date are then shown publicly on that game page for the day, week, month, and year leaderboards, ranked by time. The game never asks for a real name, a town or city, an email address, a phone number, or a school, and it rejects nicknames that look like contact information or contain words on our block list. We use a one-way hash of the network address only to limit how many posts one network can make in a short period; it is not stored with the entry.

E. Talk back (spoken answers)

Talk back is off unless an adult turns it on: a parent for one child at home, or a teacher for a class. The learner can then say an answer out loud instead of typing it. A learner cannot turn it on. The adult who turns the setting on is the consent point for it, and the keypad always stays available. Math Builders does not record or store audio, and audio is never sent to Math Builders servers. How the speech becomes a number depends on the recognizer:

• Browser speech recognition

  The browser's own speech service turns the audio into text: Chrome sends the audio to Google, Microsoft Edge to Microsoft, and Safari to Apple, under their privacy policies. Math Builders receives only the recognized text and its timing.

• On-device recognition

  The audio stays on the device. A speech model (about 41 MB) is downloaded once from Math Builders into the browser, and the answer is recognized there; no audio leaves the device. It can be removed from the device under This device in the learner's settings.

Practice uses on-device recognition once the speech model is ready on the device. Until then, and in a browser that cannot run the model, it uses browser speech recognition: the browser's speech service is used only until the model is ready. With either recognizer, the App keeps the recognized number like a typed answer, and whether the answer was spoken or typed. Math Builders does not use a cloud speech service of its own.

The voice lab, a testing tool for the adult account owner, saves each test run to that adult's own account: counts, times and the number words that were heard. It saves no audio, no other words and no names, and it is deleted with the account.

3) Optional Google Classroom roster import

A teacher or tutoring-center owner may choose to connect Google Classroom to import a roster. This connection is optional. Copying a Math Builders class link or using Share to Classroom does not connect an account or give Math Builders access to private Google Classroom data.

• Google data we access

  With the teacher’s permission, Math Builders uses read-only access to the teacher’s active Classroom courses and class roster membership. We process course name, section, and state; learner display name; and Google course and user identifiers needed to recognize the same course and roster member during re-import. We derive active or removed roster status locally from membership changes. We do not request student email addresses, profile photos, assignments, submissions, grades, guardian data, or permission to change Google Classroom.

• How we use and store Google data

  We use this data to let the teacher choose a course; create or update learner names and class membership; support the imported learner’s class-link practice, home cards, progress attribution and reporting; let the teacher create parent claim cards; identify roster changes; and show the import result. The raw selected course identifier is transiently returned to the signed-in teacher’s browser for the course picker and sent back for import. Raw Google user identifiers and all persisted client-readable provider identities use server-only or one-way keyed values. OAuth access and refresh tokens are encrypted and stored only on our server.

• Sharing and advertising

  We do not sell Google user data or use it for advertising, credit decisions, surveillance, or unrelated purposes. Our cloud service providers process it only on our behalf to operate and secure this teacher-requested feature. A teacher may share class links, home or parent-claim cards, and reports containing imported learner names for the educational workflows described here. While the teacher has opened the class, anyone with the teacher-shared class link can view that class’s name and active learner display-name list to choose a learner; when the class is closed, no names are shown and nobody can sign in through the link. Math Builders does not use, transfer, or disclose raw or derived Google Workspace API data to develop, improve, or train generalized or non-personalized artificial intelligence or machine-learning models.

• Retention, disconnection, and deletion

  A pending authorization state expires after about ten minutes. One encrypted Google connection is stored per Math Builders teacher or tutor account and can be used across classes that account owns. Disconnecting applies to all owned classes, immediately stops Math Builders from using the connection, and asks Google to revoke the grant. If Google cannot confirm revocation, Math Builders keeps only the encrypted credential and server-only cleanup record needed to retry. Cleanup stops after 10 attempts or 30 days, and Math Builders then deletes the local credential even if the Google grant can still be live. The teacher can also remove Math Builders in Google Account permissions. Learner names and roster records already imported into Math Builders remain so the classes keep working. Deleting the Math Builders account removes its classrooms, imported roster records, and import history. It removes the account identifier from any pending cleanup record but can keep the encrypted credential for the same bounded revocation period.

Math Builders' use and transfer to any other app of information received from Google APIs will adhere to the Google API Services User Data Policy, including its Limited Use requirements.

4) How we use information

• Provide core functionality

  Authenticate users, save and sync progress, schedule reviews, and load your selected packs/scenes.

• Improve and secure the App

  Monitor performance, troubleshoot issues, prevent abuse, and maintain reliability.

• Communicate

  Respond to support requests and feedback you submit through the App.

5) How we share information

We do not sell your personal information. We share information only in the following circumstances:

• Service providers

  We use Firebase (Google) to provide authentication, databases, cloud functions, file storage, and analytics. Firebase processes data on our behalf.

• Legal and safety

  We may disclose information if we believe it is reasonably necessary to comply with law, protect users, or prevent fraud or security issues.

• Business changes

  If the App is involved in a merger, acquisition, or asset transfer, information may be transferred as part of that transaction.

6) Data retention

We keep account and progress data as long as needed to provide the App. If you delete your account or request deletion, we will take reasonable steps to delete or de-identify your personal information, subject to legal, security, and operational requirements (e.g., backups and logs may persist for a limited period). Public game leaderboard entries stay on a board until that board rolls over (the daily board resets each day, the weekly board each week, the monthly board each month, and the yearly board each year); we keep an internal copy of each posted entry for up to 90 days so we can investigate and remove a nickname that should not have been posted. Anyone can ask us to remove a leaderboard entry by contacting us as described in Section 12.

7) Security

We use reasonable administrative, technical, and organizational measures designed to protect information. No method of transmission or storage is 100% secure, and we cannot guarantee absolute security.

We use reCAPTCHA to help prevent automated bot traffic. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

8) Children’s privacy (COPPA)

Please see our COPPA notice for additional information about children’s privacy.

9) Educational institutions (FERPA)

If your school uses the App, please see our FERPA notice for more details.

10) Your choices and requests

• Account choices

  You can try the signed-out sample without an account. Saving progress and syncing across devices requires either an identified adult account or a teacher-owned learner session (class link or home code) created and managed by a school; a school-authorized learner does not need a parent account to save progress this way. Historical anonymous account data may remain subject to this policy, but the App no longer offers anonymous-account save or upgrade features.

• Account deletion

  Signed-in users can permanently delete their account from the Danger Zone on the Profile page. This cancels any active subscription and removes learner profiles, practice history, classrooms, saved scenes, and sign-in credentials.

• Access requests

  You may request access to your information. Contact us via the in-app Feedback button and include the email you use for sign-in (if applicable).

• Analytics controls

  Some analytics controls may be available through your device/browser settings (e.g., blocking cookies or scripts).

11) Changes to this policy

We may update this Privacy Policy from time to time. We will change the “Last updated” date above and may provide additional notice in the App if required.

12) Contact

Questions or requests? Use the in-app Feedback button or email us at support@mathbuilders.com