This is called a slide rule. That's right. A slide rule. This is not just any old slide rule. This is my slide rule. The exact one I was required to buy as an incoming freshman at the University of Nebraska in 1971. I will now pause as you calculate my age. I often take my slide rule to class and show my students. Most don't know what it is or how to use it. They don't know that a slide rule was used to perform calculations. Invariably, a student will ask, "Why, why did the university force you to buy something like that?" The answer? Hand calculators hadn't been invented yet.
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