Ova Animations built Arithmos, a mental arithmetic training app with drills, levels, puzzles and multiplayer features. The app is free, supported by ads, and offers an optional subscription that removes ads. This policy explains what information the app collects, how it is used, and the choices you have.
By using the app, you agree to the collection and use of information as described in this policy. The developer does not sell your personal information.
Information Stored on Your Device
Drills and levels run on your device and need no account. Your levels, drill history, pet and settings are stored only on your device. Your subscription status is also kept on the device, in encrypted storage. If Android backup is on, Android may also keep a copy in your Google account's backup, which we can't access.
Signing In and Your Online Profile
Signing in is optional and uses your Google account. It is needed for leaderboards, ELO duels, friends and rooms. When you sign in, Firebase Authentication stores your account identifier, email address, name, profile photo URL and sign-in dates. The app then stores the following in Cloud Firestore:
- Your gamer id, your Google name, your country, your avatar, and your setting for sharing your name
- Your ELO rating and games played, and your best score in each drill
- Your friends list, your rival and ELO head-to-head records, rematch challenges, invites and the results inbox
- Your leaderboard entries, and your ELO duel runs that are queued for an opponent to play against
- The rooms you host, and your details in a room (gamer id, avatar, score and whether you are connected)
- A record of the account identifiers and scores of each ELO match, kept so ratings stay correct
This information is used to run these features and nothing else. Your email address is not stored in your profile. Older profiles, created before accounts used a sign-in identifier, were named with the first part of the email address; the app still reads those copies, and they are deleted with your account.
What Other Players Can See
- On leaderboards and in rooms: your gamer id, your avatar and your scores. Leaderboards also show your country
- Your Google name, if "share name" is on in Settings. It is on by default for new profiles, and you can turn it off. Your Google name is stored with your profile and leaderboard entries either way; the app only shows it when sharing is on
- In ELO standings: your ELO rating
- Other players do not see your email address
Invite Links
When you share a room invite, the app opens your phone's share sheet with a link containing the room code. The developer does not see who you send it to. Opening an invite link only passes the room code to the app so it can join that room.
Subscription
Arithmos offers a premium subscription that removes ads. Purchases are handled by Google Play Billing; we do not receive your payment details. The app asks Google Play whether you have an active subscription and stores the result on your device.
Analytics, Crash Reports and Advertising
The app uses Google Analytics for Firebase and Firebase Crashlytics to measure usage and find crashes. These collect data such as device model, operating system version, app version, IP address and crash details. This data is not linked to your account.
Free users see ads served by Google AdMob. To show and measure ads, AdMob may collect information such as your device's advertising ID, IP address, device model, operating system version and how you interact with ads. You can reset your advertising ID or opt out of personalised ads in your device's Google settings. Subscribers do not see ads.
Permissions
- Internet
- to sign in, load leaderboards, play with others, show ads and check for app updates
Third-Party Services
The app relies on the following services, which may collect information under their own privacy policies:
Data Retention and Deletion
Data stored on your device is removed when you uninstall the app or clear its storage.
Your account and online data are kept until you delete them. To delete your account, open Settings in the app and tap "delete account", or follow the steps on the Delete Your Arithmos Account page. The app deletes your data and sign-in account right away, and anything it could not reach is removed by us within 30 days.
Some data is kept after deletion: ELO match records (account identifiers and scores only, which no longer lead to any account or name), backups held by Google Cloud for up to about 6 months, and the emails and a record of your deletion request for up to 90 days. Purchases are owned by Google Play. The delete page has the full list.
Security
Data is sent over encrypted connections, and access to the database is limited by server rules so players can only change their own data. However, no method of internet transmission or electronic storage is 100% secure, and absolute security cannot be guaranteed.
Children's Privacy
This service does not address anyone under the age of 13. Personal information from children under 13 is not knowingly collected. If it is discovered that a child under 13 has provided personal information, it is promptly deleted. Parents or guardians aware of such situations should make contact for necessary action.
Changes to This Privacy Policy
This privacy policy may be updated from time to time, for example when new features are added. You are advised to review this page periodically for any changes. Updates will be posted on this page.