I took physics in eleventh grade. It’s hard to imagine, but fifty years ago, four-function (+, -, x, /) handheld calculators were new and an expensive luxury. So I learned how to use a slide rule.
My dad had a K&E slide rule he used through college and his early engineering days. I adopted it and took it to class every day to work through the math part of physics. I faintly remember getting pretty good at using a slide rule. Using logarithms, a slide rule enables you to turn a difficult multiplication or division problem into a simpler addition or subtraction problem.
In the movie Apollo 13, a whole room full of engineers pull out slide rules to figure out flight trajectories to get the three astronauts home when their capsule is damaged by an explosion.
After high school, programmable calculators became affordable, and by the time I started college in 1975, there wasn’t a slide rule to be found on campus.
Waite for it... 