Android: Calculator apps usually do nothing more than perform maths calculations. Calc+ has extra ingredients to make it more useful than its competition, including showing your last three calculations.
Calc+ gives you above-standard editing abilities, including backtracking to previous calculations to fix mistakes. It will automatically update any totals thereafter, including the steps following the fix. You can also save your equations to note taking apps like Evernote, and send your calculations to friends from right within the app. Lastly, you can store the calculator's history so you can pick up where you left off after an interruption.
The design is flat and clean with several themes available to customise the look. Check out the video to see exactly how it works.