HEXelon MAX - HEXelon MAX is a science calculator. It solves math expressions like: Sin(Pi)-Root(-8;3)+3.
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
Calculator by Xlythe - Calculator is a simple 4 function calculator.
SpeQ Mathematics - SpeQ is a small, extensive mathematics program with a simple, intuitive interface.
Console Calculator - Console Calculator is a powerful calculator with a simple console interface.
NumWorks - The graphing calculator that makes learning math easier.