(SECUSO) Improve your calculation skills in the four basic operations
About this app
Privacy Friendly Reckoning Skills helps you improving your mental calculation skills in the four basic calculating operations.
For each game, the player can choose between the four basic arithmetic operations and four difficulties (exercises up to 10, 100, 1000 and 10000).
After finishing an exercise round the player receives a score which depends on the number of exercises answered correctly and the time it took to answer all ten exercises.
After every game there is an overview which shows whether the exercises were solved correctly. It is also possible to choose "Direct Feedback" in the settings. If direct feedback is chosen, the player will receive feedback whether the exercise was solved correctly after each single exercise.
How does Privacy Friendly Reckoning Skills differ from other similar apps?
1) No permissions Privacy Friendly Reckoning Skills does not require any permissions.
For comparison: The Top Ten of similar apps from the Google Play Store requires an average of 3,4 permissions (in November 2017). These are for instance the location permission or the permissions to access, modify or delete storage.
2) No advertisement Moreover, Privacy Friendly Ludo distinguishes from many other applications in the way that it completely relinquishes advertisements. Advertisement might track a user's actions. It could also shorten battery life or use mobile data.
This App requires minimal permissions and is part of the Privacy Friendly Apps group developed by the research group SECUSO at Technische Universität Darmstadt. More information can be found at https://secuso.org/pfa
Feel free to contact us via: Bluesky - @secusoresearch.bsky.social https://bsky.app/profile/secusoresearch.bsky.social Mastodon - @SECUSO_Research@bawü.social https://xn--baw-joa.social/@SECUSO_Research/ Job opening - https://secuso.aifb.kit.edu/english/Job_Offers.php
Licensed under GPL-3.0-or-later, by SECUSO - Security Usability Society.
What's New in v1.1.2
Imported from the F-Droid repository index.
Version history
Apr 25, 2025 · 6.1 MB · Android API 17–34 · code 6
Imported from the F-Droid repository index.
SHA-256 b4d80291d6172604699f10002745831fc41fc3dde924a2da948f7767ae0a42ab
Jan 6, 2025 · 4.3 MB · Android API 17–34 · code 5
Imported from the F-Droid repository index.
SHA-256 8c0dda113d00afd48702aa4f4eac3dadca81968141197ca1ef7ab9672d423348
Oct 8, 2023 · 4 MB · Android API 17–33 · code 4
Imported from the F-Droid repository index.
SHA-256 0cd752d37677472e4933bc51900dd98256eb0182ecb3fb8a71d68a1ffbea8ac8
Will it run on your device?
73%
- Runs on a broad range of modern Android versions.
- ABI coverage is focused on newer 64-bit devices.
Installation Guide
Open Settings on your Android device
Go to Security → Unknown sources (or Install unknown apps)
Enable "Allow from this source" for your browser or file manager
Open the downloaded APK file from your Downloads folder
Tap "Install" and wait for installation to complete
Launch the app from your home screen
Make sure to re-enable Unknown Sources restrictions after installation for security.
How to install this safely
How to verify the file you downloaded
Before you install anything, confirm the file is the one described here. On a computer, run shasum -a 256 your-download.apk (macOS or Linux) or certutil -hashfile your-download.apk SHA256 (Windows), then compare the output character-for-character with the SHA-256 on this page. If a single character differs, the file is not the build we recorded — delete it.
What the signing certificate proves
Every Android app is signed with a private key that only its developer holds. The fingerprint on this page is a hash of the matching public certificate, and it proves continuity rather than identity: it tells you a build came from whoever signed the earlier ones. Android enforces this at install time — if a package claiming to be org.secuso.privacyfriendlyrecknoningskills is signed with a different key, the system will refuse to install it over your existing copy. A fingerprint that changes between releases is worth pausing on, because a repackaged app that has been modified by someone else cannot keep the original signature.
How to roll back to an earlier version
If the current release misbehaves, 1.1.1 is the last build before it. Android will not install an older version code over a newer one, so you must uninstall Reckoning Skills (Privacy Friendly) first — which clears its local data unless you have a backup. Reinstall the older APK only if its signing fingerprint matches the build you already trust, and check the API range: an older release may target an Android version your device has moved past.
Why we list sources instead of hosting everything
The official store channel is almost always the right choice: it updates automatically and carries the publisher's own distribution guarantees. A direct APK is useful when a device has no store access, when a rollout has not reached your region, or when you need a specific version — and only when the publisher has authorized that copy. APKBrowse does not list pirated, cracked, or unauthorized rebuilds of Reckoning Skills (Privacy Friendly), and a listing is removed when the evidence for it stops holding up.
Get Reckoning Skills (Privacy Friendly)
Every source we list for org.secuso.privacyfriendlyrecknoningskills is legality-reviewed. Pirated or cracked builds are never offered.
Other sources
F-Droid listing
officialF-Droid builds this app from source and signs it. This is its official listing, with older builds and full release notes.
Source code
verified publisherThe upstream repository this build is compiled from.
We check legality and signature continuity, but device behaviour still varies. Install at your own discretion.
App Information
Security Verification
We record provenance; we do not run malware scans. Verify the hash yourself before installing.
SHA-256 Hash
b4d80291d6172604699f10002745831fc41fc3dde924a2da948f7767ae0a42ab
Signing certificate
b77a83ee4174530deb64cb70515699146dd1111777755b48050ff3f2b341f502
Permissions Required
What each permission lets Reckoning Skills (Privacy Friendly) do. A highlighted one is worth a second look — not necessarily wrong, just worth asking whether this app needs it.
Previous Versions
The signing certificate fingerprint for this release is on record, so a build that does not match it did not come from this publisher.
More Games apps
More from F-Droid
Report a problem with this listing
A listing is only as good as its corrections. If a source is broken, a signature looks wrong, or this app should not be here, tell the moderation team.