(There's no video for CalcWorks SE yet. Please contribute to MR and add a video now!)
CalcWorks SE is an excessively over-fledged calculator replacement for the truely basic one that came with every Mac OS version.
There are so many options it's overwhelming! Besides calculating, it can convert measurement, mass, temperature, volume, force, power, energy and even currency units... and it comes bundled with the most popular constants such as speed of light, permeability of free space, proton mass, universal gravitation!
If you're looking for a REALLY fully fledged calculator for classic Mac OS versions, then CalcWorks SE is the one.
CalcWorks_1.7.8.sit (229.5 KiB / 235 KB)
CalcWorks SE v1.7.8 / compressed w/ Stuffit
CalcWorks_SE_1.7.6.sit (173.54 KiB / 177.71 KB)
CalcWorks SE v1.7.6 (older) / compressed w/ Stuffit
CalcWorks_1.5.3.sit_.hqx (313.08 KiB / 320.6 KB)
/ BinHex'd, use Stuffit Expander
Mac OS 6.x - Mac OS 9.2.2
At least 500KB of free RAM (recommended 1MB)
Emulating this? It should run fine under: SheepShaver