Complex equations with a specific result?

Hey, maybe someone knows enough about math and is bored enough to help me.

For a puzzle I need mathematical equations with the results 1, 2, 3 … up to 24.

I want to make an Advent calendar, but I don't want it to just have numbers on it, I want it to have an equation with the corresponding answer. The problem is that the person I'm making it for is a first-year math student and always got straight A's in his A-levels (15 points in his A-levels and so on), and I'm not good enough at math to give him challenging problems.

And for that I would also need other equations from 1-26 (for a similar idea)

Of course, I don't expect anyone here to sit down and come up with an equation for every number. But maybe for a few. That would be really nice.

Thanks in advance!