Sadly for you, Dave, the teachers from my youth are likely retired and/or dead. But, fear not, I didn’t care to “show my work” until late high school when it was mandated (as a comment upthread points out, for credit).

I ran into a situation that isn’t described: even if you’re right, they want you to prove that you didn’t cheat. Thanks to the absurdity of physics in imperial units, you can almost always show some bland dimensional conversions, but generally they love seeing an explicit change of basis for say straightforward calculus problems.

tl;dr: embrace your inner windbag, it won’t matter as long as they’re right (and one day they may appreciate it when they’re slow like us!)