Maybe other calculators can handle algrebraic expressions, but Qualculate makes it easy to see what you're doing.
It's both small and portable. You can download the tar.xz from here, https://qalculate.github.io/downloads.html , extract it and click the qualculate binary in the extracted folder.
It auto-updates. Well, my 3.3 version did to 4.4.0.