Event Viewer - Get help, support, and tutorials for Windows products—Windows 10, Windows 8.1, Windows 7, and Windows 10 Mobile.
Frink - A practical calculating tool, unit conversion utility, and programming language designed to make physical calculations simple.
Numi App - Numi is a beautiful text calculator for Mac.
NimbleText - NimbleText is a text manipulation and code generation tool available online or as a free download.
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
GeoGebra Scientific Calculator - Free online scientific calculator from GeoGebra: perform calculations with fractions, statistics and exponential functions, logarithms, trigonometry and much more!