2+2=4 is not just trivially true: Typically the symbol "4" is defined to be 3+1. (Actually it's defined as the successor of 3, but "successor" is essentially th

2+2=4 is not just trivially true: Typically the symbol "4" is defined to be 3+1. (Actually it's defined as the successor of 3, but "successor" is essentially the same as "+1"). So 2+2=4 is exactly equivalent to 2+2=3+1. This is slightly different to your identity of 2+2=1+3, because 3+1=1+3 is also non trivial. More information: https://en.m.wikipedia.org/wiki/Peano_axioms https://en.m.wikipedia.org/wiki/Peano_axioms