2 + 2 is possibly 4, but don't bank on it as did you know that 2 = 1. Not convinced? Here's the proof.
Let a = b
a^2 = ab
a^2 + a^2 = a^2 + ab
2a^2 = a^2 + ab
2a^2 - 2ab = a^2 + ab - 2ab
2(a^2 - ab) = 1(a^2 - ab)
Cancelling (a^2 - ab) from both sides gives 2 = 1