One of the scientific calculators has great business functions in a menu (ti83 maybe?). I prefered it to actual business calculators. And it could handle the science classes as well.
I don’t remember the exact model, though. Once out of school we use excel.
I carry a thin fabric zippered wallet in a front pocket along with my keys.
I have a set of keys for each car. Each set has a tracker and house key.
And a phone in the opposite front pocket.
And an Apple Watch.
That’s it. That’s all I carry. And nothing goes in a back pocket to sit awkwardly on.