Calculator Plus is described as 'nice addition to hundreds of Calculator apps but with unique idea and innovative and user friendly designed buttons' and is a Calculator in the Education & Reference category. There are more than 50 alternatives to Calculator Plus for a variety of platforms, including Windows, Android, Mac, Online / Web-based and iPhone. The best alternative is SpeedCrunch, which is both free and Open Source. Other great apps like Calculator Plus are Windows Calculator (Free, Open Source), fxSolver (Free), OpalCalc (Freemium) and Numi (Freemium).
SpeedCrunch is a free, fast, high precision open source algebraic calculator with an intuitive interface and a extensive list of features, including: Unlimited Variables, Syntax Highlighting, Functions, with 'Automagic' Completion, 50 Decimal...
A simple yet powerful calculator that includes standard, scientific, and programmer modes, as well as a unit converter. It's the perfect tool to add up a bill, convert measurements in a recipe or other project, or complete complex math, algebra, or geometry problems.
OpalCalc is a brand new type of calculator for the PC. As easy to use as Notepad or a word processor, OpalCalc allows natural language in the sum and multi-line support so you can go back and adjust your previous calculations on the fly.
Soulver is a smart notepad with a built-in calculator. It gives instant answers to any calculations it finds in your text. It's a better way to work stuff out than with a traditional calculator, and a more lightweight tool for quick calculations than a spreadsheet.