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Calculator

GitHub lbockaj/dumberkit-calculator

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Unclaimed app

The catalog lists Calculator from GitHub lbockaj/dumberkit-calculator and signs its releases. The developer has not claimed it. The file is still checked before you install it.

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How trust works

A calculator and unit converter for keypad phones like the Qin F21, Dumber Mini or Doov R77 Pro. There are no on-screen buttons: you type the calculation straight on the keypad and press OK for the result. Touch is switched off inside the app, so nothing gets pressed by accident in your pocket.

A calculator and unit converter for keypad phones like the Qin F21, Dumber Mini or Doov R77 Pro. There are no on-screen buttons: you type the calculation straight on the keypad and press OK for the result. Touch is switched off inside the app, so nothing gets pressed by accident in your pocket.

Keys • 0–9 – type numbers • * – add an operator, press it again for the next one (+ − × ÷) • Hold * – a palette of symbols laid out like the keypad: ^, √, parentheses, %, ± • # – decimal point • OK or Call – show the result • Back – delete the last character; hold it to clear everything • ↑ / ↓ – go through the history • ← / → – switch between Calculator, Unit converter and Settings

Features • The usual order of operations and exact decimals (0.1 + 0.2 = 0.3) • History like a paper tape, cleared when you close the app • Unit converter for length, area, volume, mass, temperature, time, speed, pressure and energy, in both directions • Copy the result, or take a converted value over to the calculator • System, light, dark, dark red and custom themes, a keypad-friendly color picker, blue or any other icon color • No ads, no tracking, no internet access

Based on Fossify Calculator (GPL-3.0), keypad input inspired by Calc-U-Later.

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No developer has verified this app yet, so sats go to npub1gnwq4…thdn3y, the catalog that brought it to you.

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Latest release

Oct 16, 2026

Unclaimed app No Google servicesSource available · GPL-3.0-only

The catalog lists this app from GitHub lbockaj/dumberkit-calculator and signs its releases. The developer has not claimed it. Are you the developer? Claim your app

It asks for no sensitive access.

Release notes

DumberKit: Calculator gets a currency converter.

New

  • Currency tab before the settings (dollar and yen icon): about 30 currencies at the reference rates of the European Central Bank, with the same two rows and keys as the unit converter – digits and # type the amount, ↑ / ↓ pick the row, OK lists all currencies, * swaps them
  • The rates are downloaded when you open the tab and the ones on the phone are a few hours old, or from the menu; nothing runs in the background. Offline the converter keeps working with the last rates, a copy that comes with the app covers the very first start. The line under the converter shows when the rates were downloaded
  • The app now asks for internet access – used only to download the ECB's rates

Fixed

  • The warning "You are using a fake version of the app", which showed up now and then, is gone
  • The selected button in dialogs is much easier to see
  • On phones with an on-screen navigation bar the tabs and the last rows of About stay above it

Install dumberkit-calculator.apk over the previous version, your settings stay. Requires Android 8.0 or newer.

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v2.0.4 · 71.2 MB · Android 10+

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On a computer, run shasum -a 256 <the file you downloaded>. It should print: b13e01319fecf0b3ba1fd60132758bd0fa08a235836c52d44fddb412cf1b7137

If you have zsp, Zapstore’s publishing tool, zsp utils extract-apk <the file you downloaded> works too. Its hash should be the same SHA-256: b13e01319fecf0b3ba1fd60132758bd0fa08a235836c52d44fddb412cf1b7137

On the phone, AppVerifier should show this signing certificate: 99e33b0c2d07e75fcd9df7e40e886646ff667e3aa6648e1a1160b036cf2b9320

Source code All releases and notes

Get zsp

  1. Download the file for your computer.
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Have Go? This does the same:

go install github.com/zapstore/zsp/v2/cmd/zsp@latest
macOS, Apple silicon Linux, x86-64 Linux, arm64

v2.0.1 · macOS and Linux

Verify the download

On your computer, run shasum -a 256 <the file you downloaded>. It should print the SHA-256 for the one you chose.

macOS, Apple silicon · 18.6 MB 99018fb9744e5ace2b44557550dc333496239912c0e9b1137266d4922c803346

Linux, x86-64 · 23.8 MB 1ef5373f8ecd9ba63d2c3fab98abb0d31b2244a2aac31b3749fb205c7d5f5b38

Linux, arm64 · 22.1 MB e421005ee47cba58293dce4277bb784e4cfe706dbbcb8617d671629d0238be18

Source code All releases and notes