Same. I was happy with `apt install calc` (I think nowadays called apcalc) for years because it does arbitrary precision and isn't as awkward as a python shell or so, but qalc is clearly a step up with support for units and solving

    $ calc 2^x=4
    x is undefined
    $ qalc 2^x=4
    ((2^x) = 4) = (x = 2)

I used the above for determining after how many years a given inflation rate doubles a price (1.03^x=2)

I think my most recent real-world application for units calculation was about how much energy a device uses in kWh after a year, given that it draws 10W during office hours:

    $ qalc 10W*(8h/day)*1year to kWh                                                                               
    (10 * watt) * ((8 * hour) / day) * (1 * year) = 29.22 kW*h

It even does time calculations: 13:37-08:00 tells you that you've been working for about 5.6 hours.

I don't know why this isn't the universally used command-line calculator. I have it on my phone as well via a Debian subsystem and it's the best

I use it as my calculator app on my phone