The Problem With Multiplying Complex Objects

There may be some exotic system in maths where summation is reversible if you pick the right basis for how you're doing it. But I couldn't find any, but that's maybe more the limit of my knowledge than an actual limit. And multiplying is a lot harder to do in a restaurant than addition in my humble experience. If I run a cafe, I'm going to have punch cards where you punch in your order and binary next to each item on the table. Would you have a little computer that you stick it into? Yeah. It would be quite the pop up though, wouldn't it? That cafe.