Numi App - Numi is a beautiful text calculator for Mac.
NumWorks - The graphing calculator that makes learning math easier.
Parsify Desktop - Extendable calculator for the 21st century ⚡
Rule of 3 Calculator - Apply the mathematical Rule of Three in an easier, faster and more practical way!
Soulver - Soulver is a software application that functions as a calculator that allows you type a continuous stream of information rather than having to input data into multiple cells.
eMathHelp.net - Site is created to help people learn math. Includes algebra, calculus, differential equation calculators and notes with many examples.