Once, men in short-sleeved white shirts sent people to the moon using those. What idiots.
Technically, of course, a slide rule is a calculator. It calculates, ergo it is a calculator. An abacus, likewise, is a calculator. However, looking at the slide rule just makes us think of how badly our brains have atrophied in the face of technology. Look at that thing. Do you know how to use it? Well, then congratulations on being really, really old. Sure, young people may know how to get retweets or recover someone's nude selfies from SnapChat, but those are pretty stupid skills. People used to know how to do things even if the power went out. In any case, according to the post, the teacher was giving a two-part exam, one with calculator and one without. This kid opted to take the sans-calculator portion first, and whipped out the massive slide rule (which, as mentioned, is still a calculator). While it is hilarious, he apparently didn't use it. You know, because he's not 92.