[quote][b]Posted by:[/b] Disambiguation [quote][b]Posted by:[/b] Cr4zyd4wg Maybe we could properly prove that 2+2=5, unlike the OP. [/quote][b]Lemma a[/b]: 1 = 2. [i]Proof.[/i] Let a = b. Then a^2 = ab, so 2a^2 = a^2 + ab. Then 2a^2 - 2ab = a^2 - ab, which factorizes as 2(a^2 - ab) = (a^2 - ab). Cancellation yields 1 = 2. QED. [b]Theorem:[/b] 2 + 2 = 5. [i]Proof.[/i] 2 + 2 = 3 + 1. Since 1 = 2 (by lemma a), this implies 2 + 2 = 3 + 2, which sums to 5. Therefore 2 + 2 = 5. QED.[/quote]If variable A is zero?