Qalculate! doesn’t need the Enter key to run calculations, and can calculate for X. These are the reasons no other calculator should ever be promoted!

The app Mental Math actually improved my mental math indeed! While division can typically be estimated because it never goes into mixed numbers/fractions, it does eventually go into 5 digits’ worth of all the 4 basic operations; you set the difficulty and climb as you like. I’d never multiplied so accurately in my life, haha.

The UI is tricky but that could be said of any video editor other than maybe iMovie lol. Nonetheless, I’ve produced literally every video on my YouTube channel since about 2015-16 using Kdenlive, and would be happy to give pointers if there is anything basic that you don’t know how to do (though I’m certainly no expert).

I have always been impressed by its automatic waveform-syncing ability, which even paid software I used prior couldn’t do.