Abacus is described as 'calculator for Windows and Linux that calculates while you type. It was released as free software in March 2011' and is an app in the Education & Reference category. There are more than 50 alternatives to Abacus for a variety of platforms, including Windows, Android, Mac, Android Tablet and Linux. The best alternative is SpeedCrunch, which is both free and Open Source. Other great apps like Abacus are Qalculate! (Free, Open Source), Windows Calculator (Free, Open Source), Soulver (Paid) and Calculator (Free).
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...
Qalculate! is a multi-purpose cross-platform desktop calculator. It is simple to use but provides power and versatility normally reserved for complicated math packages, as well as useful tools for everyday needs (such as currency conversion and percent calculation).
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.
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.
CalcTape is a revolutionary new kind of pocket calculator. With CalcTape, also extensive calculations remain clearly structured. CalcTape makes the arithmetic process visible - you can generate intermediate results and subsequently correct or change all numbers and operations.
A kickass, open-source calculator that lets you do calculations and unit conversions naturally, with features like: - weight conversion - length conversion - temperature conversion - currency conversion Super simple to use. Caligator works the way you think.
Programmable scientific calculator which has more than 150 mathematical functions and all of them return as many digits as you need. It can calculate with real numbers, complex numbers, fractions, vectors, matrices. Commands if, goto and print can be used to create scripts.