Wrongulator: a gag calculator that gives the wrong outcome

The Wrongulator is a gag calculator that gives incorrect answers to calculations. I'm fascinated by the idea -- I wonder if they've just got a standard calculator controller in there, and then a secondary system that scrambles the results, or whether it's a pseudorandom number generator, or what. You'd want it to produce plausible outcomes (5 x 5 = 30; not 5 x 5 = 324527) but who knows if the manufacturer paid attention to this.
The Wrongulator is no ordinary calculator, its actually the world’s worst calculator as it never gives the right answer, ever! If your calculator has been exchanged for this one then every single calculation you’ve entered in it has been wrong. It is perhaps the cruelest practical joke you could inflict on your office colleague and the chances are, without being told, they’ll probably never guess….well not before it’s too late anyway! Mwhahahaha!
Wrongulator (via Red Ferret)