I was looking at this question (writing a program such that 2 + 2 = 5) and tried to write something in Mathematica, but I couldn't get something to work without completely replacing
Plus. Neither of these worked:
Unprotect[Plus] Plus[2, 2] := 5 Unprotect[Integer] 2 + 2 ^= 5
This book suggests that
Times have special rules. Is this really impossible to do?