Engineer: 2, but 3 to be safe.
Nah not anymore, now you spend a day or so building some convoluted excel calculator once so that you never need to do the calcs again.
Then, 3 years later when you go to add or change something in that calculator, you have absolutely no idea how it works and decide the change wasn’t that important anyway.
1+1=3 in cases of large 1’s
ok, I define 1 as {∅} and 2 as {∅, {∅}}
proving the addition holds is slightly more complicated
+ is a map from N×N to N where a + 0 = a and a + S(b) = S(a + b) (S is the successor function that gives the next number).
Then 1 + 1 = 1 + S(0) = S(1 + 0) = S(1) = 2.
I really recommend the YouTube channel “Another Roof”. His first few videos were building up exactly this idea, as well as building up all the real numbers (possibly complex too if I’m remembering correctly). Sounds like a dry topic but he uses humour really well throughout. https://youtube.com/@anotherroof
Here is a playlist of the topic: https://youtube.com/playlist?list=PLsdeQ7TnWVm_EQG1rmb34ZBYe5ohrkL3t
1 + 1 is not equal to a question mark.
