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Rechenzwerge

Counting and math practice for preschool and elementary school
New in version 0.1.66
The parent area is now always reachable from the menu at the top right: tap the three dots, then "For parents". The app name on the start screen is gone, which gives the icons more room. The coin badge only appears when the games corner is switched on.
Rechenzwerge is a practice app for preschool and elementary school kids. Older kids practice the times tables and the four basic operations, the youngest count quantities without any reading. Kids who do math collect math coins and can spend them in the games corner once parents enable it.

Practice math
- Times tables (2 to 10), addition, subtraction, multiplication and division, freely combinable
- Number range up to 10, 20, 100 or 1000
- Practice rounds with 10, 50 or 100 tasks, each task appears only once
- Mistakes are fine: try again or show the solution, nothing is given away on the first try
- Results with accuracy, total time, time per task and 1 to 3 stars
- "Practice again" repeats exactly the tasks that were answered wrong
- Best scores with a progress chart per level: shows whether tasks are being solved faster over time

Practice counting (for the youngest)
- Count quantities up to 5, 10 or 20, clearly laid out in rows of five
- Two modes: pick the dice pips or place objects on the counting board
- All choices are picture tiles, no reading needed
- After counting correctly, the matching number appears and is read aloud (can be turned off)
- Calm design: one motif per round, confetti only at the end

Mascot
- Build your own mascot: color, head shape, hairstyle and accessories, or randomly with "Surprise me"
- The mascot accompanies practice with a speech bubble and cheers for correct answers

Math coins and games corner
- Tasks solved correctly on the first try earn math coins: 10 tasks make 1 coin
- After every round, the results show how many coins were added and how many tasks are left until the next coin
- The games corner is off by default and is enabled by parents
- Three mini games: Egg catch, Space and Blocks
- 5 math coins buy 3 minutes of guaranteed play time
- After that the game continues as free bonus time until all lives are used up
- A running game is never interrupted
- The level goes up every 30 seconds, also during bonus time

Parent area
- Opened with a 3-second press and hold, optionally also protected by a PIN
- Daily limit for the games corner: 15 minutes
- Enabling the games corner
- Test credit for math coins (+1, +5, +25)
- Progress per game

And also
- No real money, no in-app purchases, no ads, no tracking, no permissions
- All sounds can be turned off
- All practice data stays on the device

Versions

Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.

Download F-Droid
  • Version 0.1.66 (2066) suggested Added on Oct 29, 2026

    arm64-v8a

    This version requires Android 7.0 or newer.

    It is built and signed by the original developer, and guaranteed to correspond to this source tarball.

    Permissions
    • de.happybuers.rechenzettel.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 9 MiB PGP Signature | Build Log

  • New in version 0.1.61
    Games: rounds continue past ticket time as free bonus time until the lives run out - difficulty keeps rising. Blocks now shows a next-piece preview, Space has a black starfield and lane steps, Egg Catch adds a basket figure.
  • Version 0.1.61 (2061) - Added on Oct 27, 2026

    arm64-v8a

    This version requires Android 7.0 or newer.

    It is built and signed by the original developer, and guaranteed to correspond to this source tarball.

    Permissions
    • de.happybuers.rechenzettel.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 9 MiB PGP Signature | Build Log

  • New in version 0.1.60
    System bars stay visible (edge-to-edge) - fixes the Play review finding. Back gesture asks before leaving.
  • Version 0.1.60 (2060) - Added on Oct 25, 2026

    arm64-v8a

    This version requires Android 7.0 or newer.

    It is built and signed by the original developer, and guaranteed to correspond to this source tarball.

    Permissions
    • de.happybuers.rechenzettel.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 9 MiB PGP Signature | Build Log