Lisa's equation solver

Solve quadratic / cubic / quartic equations and systems of linear equations

Harnisch Ges.m.b.H. · at.harnisch.android.equations

Not rated yet 100K+ downloads v0.9.7t 13.4 MB Android 7.0+ PEGI 3 · Everyone

Download APK 13.4 MB All versions

Signature matches the Google Play version Details

At a glance

Latest version: v0.9.7t (49)
Updated: Aug 28, 2026 (1 month ago)
APK size: 13.4 MB
Requires: Android 7.0+ (API 24)
CPU support: x86 32-bit, x86 64-bit, ARM 32-bit, ARM 64-bit
Category: Education (app)
Listed since: Mar 13, 2021 (at least)
Permissions: 14 (2 sensitive)
Website: harnisch.at
Developer contact: [email protected]
Privacy: Developer's privacy policy

About this APK

Lisa's equation solver is an app by Harnisch Ges.m.b.H. in the Education category, listed since at least March 2021. It includes native code for x86 32-bit, x86 64-bit, ARM 32-bit and ARM 64-bit, so it runs on practically every phone.

Since version 0.9.7k, the APK grew from 8.4 MB to 13.4 MB and the minimum Android version rose from 4.4 to 7.0. It asks for 14 permissions, 2 of them sensitive: read shared storage and modify shared storage. Compared with version 0.9.7q, it adds 1 new permission: “Read basic phone state”. The app can read the advertising ID that ad and analytics services use.

What's new in v0.9.7t

★ Basic support for Android 16

Description

From the listing uploaded by “appupdater”.

Small tool to solve: - Quadratic equations - Cubic equations - Biquadratic equations - Quartic equations - Systems of 2 to 5 linear equations

Version history

5 versions are listed, going back to v0.9.7k. Since v0.9.7t it requires Android 7.0+.

v0.9.7t LATEST Aug 28, 2026 13.4 MB TRUSTED v0.9.7q Sep 8, 2025 12.9 MB TRUSTED v0.9.7p Jul 10, 2025 12 MB TRUSTED v0.9.7n Oct 8, 2024 8.4 MB TRUSTED v0.9.7k Jun 5, 2024 8.4 MB TRUSTED

All 5 versions

Security & authenticity

Security rating: Trusted

Signing certificate

Signature matches the Google Play version Checked by the source store on Aug 28, 2026.
Certificate issued to “Harnisch Ges.m.b.H.” This is the certificate of the Google Play version.
Same certificate as the 2 other versions checked

Store checks and file details

Developer signature verified Aug 28, 2026
Validated against Google Play Aug 28, 2026
Signed byCN=Werner Harnisch, O=Harnisch Ges.m.b.H., L=Wies, C=AT
Signing certificate (SHA-1)E6:BA:0B:15:59:EC:9E:33:79:7A:63:EF:AA:57:A0:39:3E:D5:7F:91
File MD5de2645726a61642b44eab5b950cc63ee
Uploaded by “appupdater” Gold tier · 117,810 followers · uploading since 2020

Scans and ratings come from the source store; the certificate comparisons are AAPKs's own, made from the files' published signatures (2 other versions compared). AAPKs doesn't scan files itself — compare the MD5 and signer after downloading.

Permissions (14)

Lisa's equation solver requests 14 permissions, 2 of them sensitive.

Modify shared storage Sensitive android.permission.WRITE_EXTERNAL_STORAGE
Read shared storage Sensitive android.permission.READ_EXTERNAL_STORAGE
Access adservices ad id android.permission.ACCESS_ADSERVICES_AD_ID
Access adservices attribution android.permission.ACCESS_ADSERVICES_ATTRIBUTION
Access adservices topics android.permission.ACCESS_ADSERVICES_TOPICS
Advertising ID com.google.android.gms.permission.AD_ID
Full network access android.permission.INTERNET
Internal broadcast protection (app-defined) at.harnisch.android.equations.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION
Prevent the device from sleeping android.permission.WAKE_LOCK
Read basic phone state android.permission.READ_BASIC_PHONE_STATE
Reorder tasks android.permission.REORDER_TASKS
Run foreground services android.permission.FOREGROUND_SERVICE
Run user initiated jobs android.permission.RUN_USER_INITIATED_JOBS
View network connections android.permission.ACCESS_NETWORK_STATE

Required hardware & features

Basic touch input android.hardware.faketouch

Lisa's equation solver APK: questions and answers

Is there a version of Lisa's equation solver for older Android phones?

The current version needs Android 7.0 or later. Version 0.9.7q is the newest listed build that installs on Android 6.0 and later. Get version 0.9.7q · All versions

Can I install this APK over the version I already have?

Yes, if your installed copy is older. It is signed like the Google Play version, so Android installs it as an update and keeps your data.

Is the Lisa's equation solver APK safe?

No one can promise that a file is safe, but some things can be checked. The source store rates this file Trusted. Its signature matches the Google Play version. It is signed with the same certificate as the 2 other versions checked. After downloading, check that the file's MD5 is de2645726a61642b44eab5b950cc63ee.