This standard algebraic calculator always stays on top, whether it's the active application or not. It's very handy when you need to go back and forth between the calculator and another window, but don't want the calculator to get lost.
All the essential functions for everyday calculation are included. Memory registers are saved, even when you quit the app.
Tod LLC Always on Top Calculator v4.0 MacOSX Retail-CORE
What's New in Version 4
Allows chained operations without needing the = key (example: 2 + 3 + 4 + 5)