Ah I see . I had imagined it was something closer to reading order which explains why I never got what I expected at least half the time . One could imagine doing some sort of very minimal animation which would make this surface every single time with only a minimal delay. Of course the minimal delay might get annoying overtime . And now that I'm thinking about it I'm not really sure how it would animate it anyway because reading order would fight you on that exactly half the time .
Yeah I had planned to add an animation where the closer number slides into the further number, just didn't end up having time for the jam . I honestly hadn't thought about it but I now realize it is kind of confusing since the tutorial levels only feature left->right subtraction, so thank you for the feedback! I guess the answer would be to have a small level where you do right-left subtraction to demonstrate how it works.