SpeQ Mathematics - SpeQ is a small, extensive mathematics program with a simple, intuitive interface.

TheTimeCalculator.org - The time calculator helps you either add/subtract times in hours, minutes, and seconds to a given date.

Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.

Calculator-online.net - The 100% free and reliable online calculators that help you to solve any calculation-related problems and provides you with the precise measurements.

NumWorks - The graphing calculator that makes learning math easier.

SpeedCrunch - SpeedCrunch. SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL. Download Documentation Donate .