Simple Dual-Platform Sum Calculator

I need a small, no-frills mobile app that lets the user enter two numbers, tap a button, and instantly see their sum. The project must ship for both Android and iOS from the same code-base, so Flutter or React Native make sense, but I am open to any toolkit that meets Apple App Store and Google Play requirements.

Core logic is straightforward—add the two numbers—but I also want the result stored locally in a running history so users can review past calculations anytime they reopen the app. No sharing features or custom UI themes are required beyond a clean, modern layout with responsive text fields and a clear results area.

I’ll consider the job complete when I receive:
• Build-ready Android (APK/AAB) and iOS (IPA) packages
• Source code with clear comments and a brief README showing how to rebuild
• Confirmation that sums persist correctly after the app is closed and relaunched on both platforms

If you have a fast turnaround and experience releasing lightweight utilities to the stores, let’s get started.