Printing Calculator
According to one of the most hilarious ads on this list, you’ll get an “instant answer, immediate proof” with the printable calculator. We’ve never heard of anything like this existing, so it comes as no surprise that it’s now obsolete. It’s incredibly funny, and says “the problem and its proof in his hands at once.” When an instant answer is needed, we can count on this calculator. Luckily, there are much better alternatives today, so we don’t have to rely on this chunky piece of technology (Pinterest).